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

[Owen Anderson via llvm-commits]

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@@ -1458,23 +1521,66 @@ permission.
 AI generated contributions
 --------------------------
 
+LLVM's policy on AI-assisted tooling is fundamentally liberal -- We want to
+enable contributors to use the latest and greatest tools available. Our policy
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resistor wrote:

"Our policy guided" -> "Our policy is guided"

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