[clang] [clang-format] Handle Trailing Whitespace After Line Continuation (P2223R2) (PR #145243)

[Björn Schäpers via cfe-commits]

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@@ -0,0 +1,14 @@
+// RUN: grep -Ev "// *[A-Z-]+:" %s \
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HazardyKnusperkeks wrote:

That's not what I meant. We test in `clang/unittests/Format/FormatTest.cpp`.

https://github.com/llvm/llvm-project/pull/145243