[clang] [clang-format] Propagate `LeadingEmptyLinesAffected` when joining lines (PR #146761)

[Eric Li via cfe-commits]

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@@ -988,6 +988,8 @@ class LineJoiner {
     assert(!B.First->Previous);
     if (B.Affected)
       A.Affected = true;
+    else if (B.LeadingEmptyLinesAffected && A.Last->Children.empty())
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tJener wrote:

Done.

https://github.com/llvm/llvm-project/pull/146761