Inline git blame (#10398)

This adds so-called "inline git blame" to the editor that, when turned
on, shows `git blame` information about the current line inline:


![screenshot-2024-04-15-11 29
35@2x](https://github.com/zed-industries/zed/assets/1185253/21cef7be-3283-4556-a9f0-cc349c4e1d75)


When the inline information is hovered, a new tooltip appears that
contains more information on the current commit:


![screenshot-2024-04-15-11 28
24@2x](https://github.com/zed-industries/zed/assets/1185253/ee128460-f6a2-48c2-a70d-e03ff90a737f)

The commit message in this tooltip is rendered as Markdown, is
scrollable and clickable.

The tooltip is now also the tooltip used in the gutter:

![screenshot-2024-04-15-11 28
51@2x](https://github.com/zed-industries/zed/assets/1185253/42be3d63-91d0-4936-8183-570e024beabe)


## Settings

1. The inline git blame information can be turned on and off via
settings:
```json
{
  "git": {
    "inline_blame": {
      "enabled": true
    }
  }
}
```
2. Optionally, a delay can be configured. When a delay is set, the
inline blame information will only show up `x milliseconds` after a
cursor movement:
```json
{
  "git": {
    "inline_blame": {
      "enabled": true,
      "delay_ms": 600
    }
  }
}
```
3. It can also be turned on/off for the current buffer with `editor:
toggle git blame inline`.

## To be done in follow-up PRs

- [ ] Add link to pull request in tooltip
- [ ] Add avatars of users if possible

## Release notes

Release Notes:

- Added inline `git blame` information the editor. It can be turned on
in the settings with `{"git": { "inline_blame": "on" } }` for every
buffer or, temporarily for the current buffer, with `editor: toggle git
blame inline`.

crates/project/src/project.rs

@@ -7756,13 +7756,20 @@ impl Project {
                     .as_local()
                     .context("worktree was not local")?
                     .snapshot();
-                let (work_directory, repo) = worktree
-                    .repository_and_work_directory_for_path(&buffer_project_path.path)
-                    .context("failed to get repo for blamed buffer")?;
 
-                let repo_entry = worktree
-                    .get_local_repo(&repo)
-                    .context("failed to get repo for blamed buffer")?;
+                let (work_directory, repo) = match worktree
+                    .repository_and_work_directory_for_path(&buffer_project_path.path)
+                {
+                    Some(work_dir_repo) => work_dir_repo,
+                    None => anyhow::bail!(NoRepositoryError {}),
+                };
+
+                let repo_entry = match worktree.get_local_repo(&repo) {
+                    Some(repo_entry) => repo_entry,
+                    None => anyhow::bail!(NoRepositoryError {}),
+                };
+
+                let repo = repo_entry.repo().clone();
 
                 let relative_path = buffer_project_path
                     .path
@@ -7773,7 +7780,6 @@ impl Project {
                     Some(version) => buffer.rope_for_version(&version).clone(),
                     None => buffer.as_rope().clone(),
                 };
-                let repo = repo_entry.repo().clone();
 
                 anyhow::Ok((repo, relative_path, content))
             });
@@ -10782,3 +10788,14 @@ fn remove_empty_hover_blocks(mut hover: Hover) -> Option<Hover> {
         Some(hover)
     }
 }
+
+#[derive(Debug)]
+pub struct NoRepositoryError {}
+
+impl std::fmt::Display for NoRepositoryError {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "no git repository for worktree found")
+    }
+}
+
+impl std::error::Error for NoRepositoryError {}