urltools: add readme (#7126)

plugins/urltools/README.md

+# URLTools plugin
+
+This plugin provides two aliases to URL-encode and URL-decode strings.
+
+To start using it, add the `urltools` plugin to your plugins array in `~/.zshrc`:
+
+```zsh
+plugins=(... urltools)
+```
+
+Original author: [Ian Chesal](https://github.com/ianchesal)
+Original idea and aliases: [Ruslan Spivak](https://ruslanspivak.wordpress.com/2010/06/02/urlencode-and-urldecode-from-a-command-line/)
+
+## Commands
+
+| Command     | Description                  |
+| :---------- | :--------------------------- |
+| `urlencode` | URL-encodes the given string |
+| `urldecode` | URL-decodes the given string |
+
+## Examples
+
+```zsh
+urlencode 'https://github.com/robbyrussell/oh-my-zsh/search?q=urltools&type=Code'
+# returns https%3A%2F%2Fgithub.com%2Frobbyrussell%2Foh-my-zsh%2Fsearch%3Fq%3Durltools%26type%3DCode
+
+urldecode 'https%3A%2F%2Fgithub.com%2Frobbyrussell%2Foh-my-zsh%2Fsearch%3Fq%3Durltools%26type%3DCode'
+# returns https://github.com/robbyrussell/oh-my-zsh/search?q=urltools&type=Code
+```