[clang] clang-format: Add IncludeSortKey option (PR #137840)

[Björn Schäpers via cfe-commits]

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@@ -166,6 +166,16 @@ struct IncludeStyle {
   /// directives that use the specified character are considered.
   /// \version 19
   MainIncludeCharDiscriminator MainIncludeChar;
+
+  enum IncludeSortKeyDiscriminator : int8_t {
+    /// Includes are sorted alphabetically by their full path.
+    ISK_Path,
+    /// Includes are sorted alphabetically by their full path without file
+    /// extension.
+    ISK_Stem,
+  };
+
+  IncludeSortKeyDiscriminator IncludeSortKey;
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HazardyKnusperkeks wrote:

You need to initialize this, in `Format.cpp` around line 1585.

https://github.com/llvm/llvm-project/pull/137840