docs: Add configuration explanation in git section (#43637)

Matthew Chisolm and Jakub Konka created 

Closes https://github.com/zed-industries/zed/issues/33441

Release Notes:

- Added configuration documentation for git-commit settings including preferred-line-length in the git panel

---------

Co-authored-by: Jakub Konka <kubkon@jakubkonka.com>

Change summary

docs/src/git.md | 23 +++++++++++++++++++++++
1 file changed, 23 insertions(+)

Detailed changes

docs/src/git.md 🔗 

@@ -29,6 +29,23 @@ In the panel you can see the state of your project at a glance—which repositor
 
 Zed monitors your repository so that changes you make on the command line are instantly reflected.
 
+### Configuration
+
+You can configure how Zed hard wraps commit messages with the `preferred-line-length` setting of the "Git Commit" language. The default is `72`, but it can be set to any number of characters `0` or more.
+
+The Git Panel also allows configuring the `soft_wrap` setting to adjust how commit messages display while you are typing them in the Git Panel. The default setting is `editor_width`, however, `none`, `preferred_line_length`, and `bounded` are also options.
+
+#### Example
+
+```json
+"languages": {
+  "Git Commit": {
+    "soft_wrap": "editor_width",
+    "preferred_line_length": 72
+  },
+}
+```
+
 ## Project Diff
 
 You can see all of the changes captured by Git in Zed by opening the Project Diff ({#kb git::Diff}), accessible via the {#action git::Diff} action in the Command Palette or the Git Panel.
@@ -75,6 +92,12 @@ Zed offers two commit textareas:
 As soon as you commit in Zed, in the Git Panel, you'll see a bar right under the commit textarea, which will show the recently submitted commit.
 In there, you can use the "Uncommit" button, which performs the `git reset HEADˆ--soft` command.
 
+### Configuring Commit Line Length
+
+By default, Zed sets the commit line length to `72` but it can be configured in your local `settings.json` file.
+
+Find more information about setting the `preferred-line-length` in the [Configuration](#configuration) section.
+
 ## Stashing
 
 Git stash allows you to temporarily save your uncommitted changes and revert your working directory to a clean state. This is particularly useful when you need to quickly switch branches or pull updates without committing incomplete work.