docs: Add Shell Script language documentation (#23248)

docs/src/languages/bash.md

@@ -8,17 +8,29 @@ Report issues to: [https://github.com/d1y/bash.zed/issues](https://github.com/d1
 
 ## Configuration
 
-The bash-language-server support shellcheck. But you need to install it manually:
+When `shellcheck` is available `bash-language-server` will use it internally to provide diagnostics.
+
+### Install `shellcheck`:
 
 ```sh
-# macOS
-brew install shellcheck
+brew install shellcheck             # macOS (HomeBrew)
+apt-get install shellcheck          # Ubuntu/Debian
+pacman -S shellcheck                # ArchLinux
+dnf install shellcheck              # Fedora
+yum install shellcheck              # CentOS/RHEL
+zypper install shellcheck           # openSUSE
+choco install shellcheck            # Windows (Chocolatey)
+```
 
-# Ubuntu/Debian
-sudo apt-get install shellcheck
+And verify it is available from your path:
 
-# Arch Linux
-pacman -S shellcheck
+```sh
+which shellcheck
+shellcheck --version
 ```
 
 If you wish to customize the warnings/errors reported you just need to create a `.shellcheckrc` file. You can do this in the root of your project or in your home directory (`~/.shellcheckrc`). See: [shellcheck documentation](https://github.com/koalaman/shellcheck/wiki/Ignore#ignoring-one-or-more-types-of-errors-forever) for more.
+
+### See also:
+
+- [Zed Docs: Language Support: Shell Scripts](./sh.md)