Don't allow open excerpts in commit view for now (#27862)

Follow-up to https://github.com/zed-industries/zed/pull/27636

Release Notes:

- N/A

crates/editor/src/editor.rs

@@ -17212,6 +17212,9 @@ impl Editor {
             }
         }
 
+        new_selections_by_buffer
+            .retain(|buffer, _| Self::can_open_excerpts_in_file(buffer.read(cx).file()));
+
         if new_selections_by_buffer.is_empty() {
             return;
         }
@@ -17280,6 +17283,12 @@ impl Editor {
         });
     }
 
+    // For now, don't allow opening excerpts in buffers that aren't backed by
+    // regular project files.
+    fn can_open_excerpts_in_file(file: Option<&Arc<dyn language::File>>) -> bool {
+        file.map_or(true, |file| project::File::from_dyn(Some(file)).is_some())
+    }
+
     fn marked_text_ranges(&self, cx: &App) -> Option<Vec<Range<OffsetUtf16>>> {
         let snapshot = self.buffer.read(cx).read(cx);
         let (_, ranges) = self.text_highlights::<InputComposition>(cx)?;

crates/editor/src/element.rs

@@ -2791,6 +2791,7 @@ impl EditorElement {
             .as_ref()
             .map(|project| project.read(cx).visible_worktrees(cx).count() > 1)
             .unwrap_or_default();
+        let can_open_excerpts = Editor::can_open_excerpts_in_file(for_excerpt.buffer.file());
         let path = for_excerpt.buffer.resolve_file_path(cx, include_root);
         let filename = path
             .as_ref()
@@ -2920,7 +2921,7 @@ impl EditorElement {
                                         ))
                                     }),
                             )
-                            .when(is_selected, |el| {
+                            .when(can_open_excerpts && is_selected && path.is_some(), |el| {
                                 el.child(
                                     h_flex()
                                         .id("jump-to-file-button")