[clang] [libcxx] [libc++][Clang] Added explanation why is_constructible evaluated to false. Updated the diagnostics checks in libc++ tests. (PR #144220)

[Ross Kirsling via cfe-commits]

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@@ -1767,7 +1767,8 @@ def note_unsatisfied_trait
     : Note<"%0 is not %enum_select<TraitName>{"
            "%TriviallyRelocatable{trivially relocatable}|"
            "%Replaceable{replaceable}|"
-           "%TriviallyCopyable{trivially copyable}"
+           "%TriviallyCopyable{trivially copyable}|"
+           "%Constructible{constructible with provided types}"
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rkirsling wrote:

Looks like this is no longer used in the latest version of the patch?

https://github.com/llvm/llvm-project/pull/144220