[clang] [clang-tools-extra] [clang] Make 'fileScopeAsmDecl' matcher public (PR #165319)

[Baranov Victor via cfe-commits]

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@@ -2478,6 +2478,16 @@ extern const internal::VariadicDynCastAllOfMatcher<Stmt, NullStmt> nullStmt;
 ///   matches '__asm("mov al, 2")'
 extern const internal::VariadicDynCastAllOfMatcher<Stmt, AsmStmt> asmStmt;
 
+/// Matches top level asm declarations.
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vbvictor wrote:

What is the difference between top-level and not top-level asm declarations?
The ` __asm` isn't top level?

Could we provide here example of non-top level declaration which wouldn't match

https://github.com/llvm/llvm-project/pull/165319