Add setting to hide active language button in the status bar (#33977)

Release Notes:

- Added settings status_bar.show_active_language_button to show/hide the
language button in the status bar.

The motivation for this is visual, I have had zero issues with its
functionality.

The language switcher can still be accessed by the command palette,
menu, or a keyboard shortcut.

------

This is my first Zed and first Rust PR, so criticism is very welcome. 

I know there has been discussion around how the status bar settings are
structured and named, and I am happy to change it to whatever is best. I
was also not sure what order to put it in in the settings default.json.
Feedback welcome.

Here is a picture of it in action:


![image](https://github.com/user-attachments/assets/c50131e2-71aa-4fab-8db0-8b2aae586e71)

---------

Co-authored-by: zumbalogy <3770982+zumbalogy@users.noreply.github.com>
Co-authored-by: Kirill Bulatov <kirill@zed.dev>

docs/src/configuring-zed.md

@@ -1275,6 +1275,18 @@ Each option controls displaying of a particular toolbar element. If all elements
 
 `boolean` values
 
+## Status Bar
+
+- Description: Control various elements in the status bar. Note that some items in the status bar have their own settings set elsewhere.
+- Setting: `status_bar`
+- Default:
+
+```json
+"status_bar": {
+  "active_language_button": true,
+},
+```
+
 ## LSP
 
 - Description: Configuration for language servers.

docs/src/visual-customization.md

@@ -306,6 +306,17 @@ TBD: Centered layout related settings
   }
 ```
 
+### Status Bar
+
+```json
+  "status_bar": {
+    // Show/hide a button that displays the active buffer's language.
+    // Clicking the button brings up the language selector.
+    // Defaults to true.
+    "active_language_button": true,
+  },
+```
+
 ### Multibuffer
 
 ```json