Fix missing 'git' prefix in GitGuide.md example

[oharboe]

No description provided.

[gemini-code-assist]

Code Review

This pull request correctly fixes a typo in a git command example in GitGuide.md. I've also added a suggestion to simplify the example code block to make it more concise and easier for beginners to understand.

_{Note: Security Review has been skipped due to the limited scope of the PR.}

[gemini-code-assist]

While your fix for the typo is correct, the entire example block could be simplified to be more direct and idiomatic for a git quickstart guide. The current examples are a bit verbose and show a non-standard way of creating a branch. A single command can achieve the desired outcome of creating a new branch from master and switching to it, which is clearer for new contributors.

Suggested change

	git checkout master && git branch shiny-new-feature
	git checkout shiny-new-feature
	# Or equivalently,
	git checkout master && checkout -b shiny-new-feature
	git checkout master && git checkout -b shiny-new-feature
	# Create a new branch 'shiny-new-feature' from 'master' and switch to it
	git checkout -b shiny-new-feature master

[github-actions]

clang-tidy review says "All clean, LGTM! 👍"