Expose "Column Git Blame" in the editor controls menu (#21336)

Closes https://github.com/zed-industries/zed/issues/10196

I think having this action exposed in the editor controls menu, close to
the inline Git Blame option, makes more sense than a more prominent item
somewhere else in the app. Maybe having it there will increase its
discoverability. I myself didn't know this until a few weeks ago! Next
steps would be ensuring the menu exposes its keybindings.

(Quick note about the menu item name: I think maybe "_Git Blame Column_"
would make more sense and feel grammatically more correct, but then we
would have two Git Blame-related options, one with "Git Blame" at the
start (Inline...) and another with "Git Blame" at the end (... Column).
I guess one had to be sacrificed for the sake of consistency 😅.)

<img width="750" alt="Screenshot 2024-11-29 at 12 01 33"
src="https://github.com/user-attachments/assets/2f3324ec-a2f0-4303-9582-714d0ee6bd31">

Release Notes:

- N/A

crates/editor/src/editor.rs

@@ -11796,6 +11796,10 @@ impl Editor {
         self.blame.as_ref()
     }
 
+    pub fn show_git_blame_gutter(&self) -> bool {
+        self.show_git_blame_gutter
+    }
+
     pub fn render_git_blame_gutter(&mut self, cx: &mut WindowContext) -> bool {
         self.show_git_blame_gutter && self.has_blame_entries(cx)
     }