Remove godoc.org references (#5219)

* remove github.com/posener/tarfs

- has not been updated for 7 years.
- implements the github.com/kr/fs#FileSystem (and not the stdlib io.FS interface), package which has been replaced by kr.dev/walk

* Cleanup godoc.org

- remove package with no tagged version
- update documentation link to pkg.go.dev for maintained libraries

* adjust pkg.go.dev position

* gowalker.org does not serve Go content

README.md

@@ -1092,7 +1092,6 @@ _Libraries for handling files and file systems._
 - [pdfcpu](https://github.com/pdfcpu/pdfcpu) - PDF processor.
 - [skywalker](https://github.com/dixonwille/skywalker) - Package to allow one to concurrently go through a filesystem with ease.
 - [stl](https://gitlab.com/russoj88/stl) - Modules to read and write STL (stereolithography) files. Concurrent algorithm for reading.
-- [tarfs](https://github.com/posener/tarfs) - Implementation of the [`FileSystem` interface](https://godoc.org/github.com/kr/fs#FileSystem) for tar files.
 - [todotxt](https://github.com/1set/todotxt) - Go library for Gina Trapani's [_todo.txt_](http://todotxt.org/) files, supports parsing and manipulating of task lists in the [_todo.txt_ format](https://github.com/todotxt/todo.txt).
 - [vfs](https://github.com/C2FO/vfs) - A pluggable, extensible, and opinionated set of filesystem functionality for Go across a number of filesystem types such as os, S3, and GCS.
 
@@ -2169,7 +2168,7 @@ _Libraries that are used to help make your application more secure._
 - [age](https://github.com/FiloSottile/age) - A simple, modern and secure encryption tool (and Go library) with small explicit keys, no config options, and UNIX-style composability.
 - [argon2-hashing](https://github.com/andskur/argon2-hashing) - light wrapper around Go's argon2 package that closely mirrors with Go's standard library Bcrypt and simple-scrypt package.
 - [argon2pw](https://github.com/raja/argon2pw) - Argon2 password hash generation with constant-time password comparison.
-- [autocert](https://godoc.org/golang.org/x/crypto/acme/autocert) - Auto provision Let's Encrypt certificates and start a TLS server.
+- [autocert](https://pkg.go.dev/golang.org/x/crypto/acme/autocert) - Auto provision Let's Encrypt certificates and start a TLS server.
 - [BadActor](https://github.com/jaredfolkins/badactor) - In-memory, application-driven jailer built in the spirit of fail2ban.
 - [beelzebub](https://github.com/mariocandela/beelzebub) - A secure low code honeypot framework, leveraging AI for System Virtualization.
 - [booster](https://github.com/anatol/booster) - Fast initramfs generator with full-disk encryption support.
@@ -2368,7 +2367,6 @@ _Libraries for testing codebases and generating test data._
   - [testcontainers-go](https://github.com/testcontainers/testcontainers-go) - A Go package that makes it simple to create and clean up container-based dependencies for automated integration/smoke tests. The clean, easy-to-use API enables developers to programmatically define containers that should be run as part of a test and clean up those resources when the test is done.
   - [testfixtures](https://github.com/go-testfixtures/testfixtures) - A helper for Rails' like test fixtures to test database applications.
   - [Testify](https://github.com/stretchr/testify) - Sacred extension to the standard go testing package.
-  - [testmd](https://godoc.org/github.com/tvastar/test/cmd/testmd) - Convert markdown snippets into testable go code.
   - [testsql](https://github.com/zhulongcheng/testsql) - Generate test data from SQL files before testing and clear it after finished.
   - [testza](https://github.com/MarvinJWendt/testza) - Full-featured test framework with nice colorized output.
   - [trial](https://github.com/jgroeneveld/trial) - Quick and easy extendable assertions without introducing much boilerplate.
@@ -2436,7 +2434,6 @@ See also [Natural Language Processing](#natural-language-processing) and [Text A
 - [bafi](https://github.com/mmalcek/bafi) - Universal JSON, BSON, YAML, XML translator to ANY format using templates.
 - [bbConvert](https://github.com/CalebQ42/bbConvert) - Converts bbCode to HTML that allows you to add support for custom bbCode tags.
 - [blackfriday](https://github.com/russross/blackfriday) - Markdown processor in Go.
-- [github_flavored_markdown](https://godoc.org/github.com/shurcooL/github_flavored_markdown) - GitHub Flavored Markdown renderer (using blackfriday) with fenced code block highlighting, clickable header anchor links.
 - [go-output-format](https://github.com/drewstinnett/go-output-format) - Output go structures into multiple formats (YAML/JSON/etc) in your command line app.
 - [go-toml](https://github.com/pelletier/go-toml) - Go library for the TOML format with query support and handy cli tools.
 - [goldmark](https://github.com/yuin/goldmark) - A Markdown parser written in Go. Easy to extend, standard (CommonMark) compliant, well structured.
@@ -3069,7 +3066,7 @@ _Source code analysis tools, also known as Static Application Security Testing (
 - [go-mod-outdated](https://github.com/psampaz/go-mod-outdated) - An easy way to find outdated dependencies of your Go projects.
 - [go-outdated](https://github.com/firstrow/go-outdated) - Console application that displays outdated packages.
 - [goast-viewer](https://github.com/yuroyoro/goast-viewer) - Web based Golang AST visualizer.
-- [goimports](https://godoc.org/golang.org/x/tools/cmd/goimports) - Tool to fix (add, remove) your Go imports automatically.
+- [goimports](https://pkg.go.dev/golang.org/x/tools/cmd/goimports) - Tool to fix (add, remove) your Go imports automatically.
 - [golang-ifood-sdk](https://github.com/arxdsilva/golang-ifood-sdk) - iFood API SDK.
 - [golangci-lint](https://github.com/golangci/golangci-lint) – A fast Go linters runner. It runs linters in parallel, uses caching, supports `yaml` config, has integrations with all major IDE and has dozens of linters included.
 - [golines](https://github.com/segmentio/golines) - Formatter that automatically shortens long lines in Go code.
@@ -3555,7 +3552,6 @@ _Add the group of your city/country here (send **PR**)_
 - [Go Report Card](https://goreportcard.com) - A report card for your Go package.
 - [go.dev](https://go.dev/) - A hub for Go developers.
 - [gocryforhelp](https://github.com/ninedraft/gocryforhelp) - Collection of Go projects that needs help. Good place to start your open-source way in Go.
-- [godoc.org](https://godoc.org/) - Documentation for open source Go packages.
 - [Golang Developer Jobs](https://golangjob.xyz) - Developer Jobs exclusively for Golang related Roles.
 - [Golang Flow](https://golangflow.io) - Post Updates, News, Packages and more.
 - [Golang News](https://golangnews.com) - Links and news about Go programming.
@@ -3566,11 +3562,11 @@ _Add the group of your city/country here (send **PR**)_
 - [Google Plus Community](https://plus.google.com/communities/114112804251407510571) - The Google+ community for #golang enthusiasts.
 - [Gopher Community Chat](https://invite.slack.golangbridge.org) - Join Our New Slack Community For Gophers ([Understand how it came](https://blog.gopheracademy.com/gophers-slack-community/)).
 - [Gophercises](https://gophercises.com/) - Free coding exercises for budding gophers.
-- [gowalker.org](https://gowalker.org) - Go Project API documentation.
 - [json2go](https://m-zajac.github.io/json2go) - Advanced JSON to Go struct conversion - online tool.
 - [justforfunc](https://www.youtube.com/c/justforfunc) - Youtube channel dedicated to Go programming language tips and tricks, hosted by Francesc Campoy [@francesc](https://twitter.com/francesc).
 - [Learn Go Programming](https://blog.learngoprogramming.com) - Learn Go concepts with illustrations.
 - [Made with Golang](https://madewithgolang.com/?ref=awesome-go)
+- [pkg.go.dev](https://pkg.go.dev/) - Documentation for open source Go packages.
 - [r/Golang](https://www.reddit.com/r/golang) - News about Go.
 - [studygolang](https://studygolang.com) - The community of studygolang in China.
 - [Trending Go repositories on GitHub today](https://github.com/trending?l=go) - Good place to find new Go libraries.