"diff" part of verbose commits should be ignored

[MithicSpirit]

Describe the bug
The diff part of a verbose commit message (see man git-commit(1)) is treated as text and often leads to MANY errors since it's usuallyc ode.

Steps to reproduce
Steps to reproduce the behavior:

1. Set your $EDITOR to something with ltex-ls support.
2. Run git commit -v on some repository
3. Wait for the excessive diagnostics to show up

Expected behavior
The diff part would be ignored and no diagnostics would show up.

LTeX configuration
No relevant settings.

Version information
List here the version information of the relevant software.

• Operating system: Arch Linux
• ltex-ls: 16.0.0
• Java: openjdk 22