docs: fix typo [no ci] (ggml-org#16244)

Author: JohannesGaessler

CONTRIBUTING.md

@@ -25,7 +25,7 @@ The project differentiates between 3 levels of contributors:
 - Squash-merge PRs
 - Use the following format for the squashed commit title: `<module> : <commit title> (#<issue_number>)`. For example: `utils : fix typo in utils.py (#1234)`
 - Optionally pick a `<module>` from here: https://github.com/ggml-org/llama.cpp/wiki/Modules
-- Let other maintainers, merge their own PRs
+- Let other maintainers merge their own PRs
 - When merging a PR, make sure you have a good understanding of the changes
 - Be mindful of maintenance: most of the work going into a feature happens after the PR is merged. If the PR author is not committed to contribute long-term, someone else needs to take responsibility (you)