[clang-tools-extra] [clang-tidy] introduce a must use check (PR #76101)

[Tyler Rockwood via cfe-commits]

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@@ -54,6 +55,7 @@ class MiscModule : public ClangTidyModule {
     CheckFactories.registerCheck<MisleadingIdentifierCheck>(
         "misc-misleading-identifier");
     CheckFactories.registerCheck<MisplacedConstCheck>("misc-misplaced-const");
+    CheckFactories.registerCheck<MustUseCheck>("misc-must-use");
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rockwotj wrote:

Merging that check and mine STGM (as well as the naming of your check). Do you have source for your check you'd like to point to? Otherwise I'm happy to add in a lot of these.

https://github.com/llvm/llvm-project/pull/76101