contrib : merge PR sections + add link to CI instructions

Updated pull request guidelines for contributors and collaborators, and clarified merging practices for maintainers.

Author: ggerganov

CONTRIBUTING.md

@@ -6,7 +6,7 @@ The project differentiates between 3 levels of contributors:
 - Collaborators (Triage): people with significant contributions, who may be responsible for some parts of the code, and are expected to maintain and review contributions for the code they own
 - Maintainers: responsible for reviewing and merging PRs, after approval from the code owners
 
-# Pull requests (for contributors)
+# Pull requests (for contributors & collaborators)
 
 - llama.cpp uses the ggml tensor library for model evaluation. If you are unfamiliar with ggml, consider taking a look at the [examples in the ggml repository](https://github.com/ggml-org/ggml/tree/master/examples/). [simple](https://github.com/ggml-org/ggml/tree/master/examples/simple) shows the bare minimum for using ggml. [gpt-2](https://github.com/ggml-org/ggml/tree/master/examples/gpt-2) has minimal implementations for language model inference using GPT-2. [mnist](https://github.com/ggml-org/ggml/tree/master/examples/mnist) demonstrates how to train and evaluate a simple image classifier
 - Test your changes:
@@ -17,9 +17,6 @@ The project differentiates between 3 levels of contributors:
 - Create separate PRs for each feature or fix. Avoid combining unrelated changes in a single PR
 - Consider allowing write access to your branch for faster reviews, as reviewers can push commits directly
 - If your PR becomes stale, don't hesitate to ping the maintainers in the comments
-
-# Pull requests (for collaborators)
-
 - Maintainers will rely on your insights and approval when making a final decision to approve and merge a PR
 - Consider adding yourself to [CODEOWNERS](CODEOWNERS) to indicate your availability for reviewing related PRs
 
@@ -29,7 +26,7 @@ The project differentiates between 3 levels of contributors:
 - 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
-- When merging a PR by a contributor, make sure you have a good understanding of the changes
+- 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)
 
 # Coding guidelines
@@ -139,7 +136,7 @@ The project differentiates between 3 levels of contributors:
 - When adding or modifying a large piece of code:
   - If you are a collaborator, make sure to add yourself to [CODEOWNERS](CODEOWNERS) to indicate your availability for reviewing related PRs
   - If you are a contributor, find an existing collaborator who is willing to review and maintain your code long-term
-  - Provide the necessary CI workflow (and hardware) to test your changes
+  - Provide the necessary CI workflow (and hardware) to test your changes (see [ci/README.md](https://github.com/ggml-org/llama.cpp/tree/master/ci))
 
 - New code should follow the guidelines (coding, naming, etc.) outlined in this document. Exceptions are allowed in isolated, backend-specific parts of the code that do not interface directly with the `ggml` interfaces.
   _(NOTE: for legacy reasons, existing code is not required to follow this guideline)_