Update AddStateBagChangeHandler.md C# example

[horseyhorsey]

Goal of this PR

C# documentation added snippet

[spacevx]

it's cs not c# in the ```

[FabianTerhorst]

@horseyhorsey I mean the commit message itself, not the pull request title. When you don't know how it works use https://docs.github.com/en/desktop/managing-commits/amending-a-commit-in-github-desktop or reopen the pull request with a new branch.

[FabianTerhorst]

We will manually edit the commit text on merge.

[FabianTerhorst]

Merged https://github.com/citizenfx/fivem/commit/1f062c0476f0f07a6370b6b0cd9fb9cd80a8b066