[clang] [clang-format] Add MainIncludeChar option. (PR #78752)

[Björn Schäpers via cfe-commits]

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@@ -151,6 +151,21 @@ struct IncludeStyle {
   /// before any other include.
   /// \version 10
   std::string IncludeIsMainSourceRegex;
+
+  /// Character to consider in the include directives for the main header.
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HazardyKnusperkeks wrote:

It should also be added to `FormatStyle::operator==` in `Format.h`.

https://github.com/llvm/llvm-project/pull/78752