[llvm] [docs] Strengthen our quality standards and connect AI contribution policy to it (PR #154441)

[Reid Kleckner via llvm-commits]

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@@ -293,57 +293,63 @@ warranted when performing a code review.
 Quality
 -------
 
-The minimum quality standards that any change must satisfy before being
-committed to the main development branch are:
-
-#. Code must adhere to the `LLVM Coding Standards <CodingStandards.html>`_.
-
-#. Code must compile cleanly (no errors, no warnings) on at least one platform.
+Sending patches, PRs, RFCs, comments, etc to LLVM, is not free -- it takes a lot
+of maintainer time and energy to review those contributions. Our quality bar can
+be summarized with the **golden rule** that a contribution should be worth more
+to the project than the time it takes to review it.
+
+However, this rule is held in balance with our goal to make the LLVM project
+welcoming and open to aspiring compiler engineers who are willing to invest time
+and effort to learn and grow, because growing our contributor base and
+potentially recruiting new maintainers helps sustain the project over the long
+term.
+
+Contributors who repeatedly make low-value contributions according to the
----------------
rnk wrote:

I implemented this in the last push

https://github.com/llvm/llvm-project/pull/154441