[clang-tools-extra] Fix #35272: Don't replace typedefs in extern c scope (PR #69102)

[Piotr Zegar via cfe-commits]

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@@ -28,6 +28,13 @@ After:
   using R_t = struct { int a; };
   using R_p = R_t*;
 
+The checker ignores `typedef` within `extern "C" { ... }` blocks.
+
+.. code-block:: c++
+  extern "C" {
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PiotrZSL wrote:

put empty line here, this is why documentation fails

https://github.com/llvm/llvm-project/pull/69102