Edit commit message

### Godot version

v4.7.1.stable.official [a13da4feb]

### Godot Git Plugin version

3.2.1

### System information

Windows 11

### Problem statement

Given I have committed with a message.

When I right click on the message (marked yellow)

I would expect a context menu where I can choose to edit the message.

### Proposed solution

Like its possible in other editors like PHPStorm.

How to do that in terminal: https://stackoverflow.com/questions/179123/how-to-modify-existing-unpushed-commit-messages

Start by locating the Godot Git Plugin code that displays committed messages and handles their context-menu actions, then trace how existing Git operations are exposed there. Define the edit-message interaction for unpushed commits and verify it against the commit history UI on Windows; the feature is done when a message can be edited through that context menu and the resulting commit history reflects it.

Written by the indexing model from the issue text.