add uninstall instructions (#5311)

it's always good to have uninstall instructions as well as install, and I couldn't find them anywhere else on the site.

IMO, this gives users a little more confidence to try new tools out, as they know it's easily reversible.

I'm not familiar with how to uninstall with Docker, so would appreciate some help there.

We could possibly add a note for "bash" on how to remove Bun from the `$PATH`.

docs/installation.md

@@ -149,3 +149,27 @@ To write the completions to a custom location:
 $ bun completions > path-to-file      # write to file
 $ bun completions /path/to/directory  # write into directory
 ```
+
+## Uninstall
+
+If you need to remove Bun from your system, use the following commands.
+
+{% codetabs %}
+
+```bash#macOS/Linux_(curl)
+$ rm -rf ~/.bun # for macOS, Linux, and WSL
+```
+
+```bash#NPM
+$ npm uninstall -g bun
+```
+
+```bash#Homebrew
+$ brew uninstall bun
+```
+
+```bash#Proto
+$ proto uninstall bun
+```
+
+{% /codetabs %}