[NFC][clang-tools-extra] Inclusive language: replace master with main

[quinnp]

Summary

[NFC] As part of using inclusive language within the llvm project, this patch
replaces master with main in SubModule2.h.

[sammccall]

clang-tools-extra/clangd/Protocol.h

141

This is quoting https://microsoft.github.io/language-server-protocol/specification.
I think they accept PRs though.

[quinnp]

clang-tools-extra/clangd/Protocol.h

141

Thanks @sammccall, I'll remove this change from the patch.

[quinnp]

Addressing review comments. Reverting change to Protocol.h.

[quinnp]

@sammccall could you take a look at the other changes when you have time? Thanks!

[sammccall]

Sorry, LG!
(I'm not very familiar with clang-modularize, but this seems to be the only place the term is used)

clang-tools-extra/clangd/Protocol.h

 bool fromJSON(const llvm::json::Value &, TextDocumentIdentifier &,
               llvm::json::Path);
 
 struct VersionedTextDocumentIdentifier : public TextDocumentIdentifier {
   /// The version number of this document. If a versioned text document
   /// identifier is sent from the server to the client and the file is not open
   /// in the editor (the server has not received an open notification before)
   /// the server can send `null` to indicate that the version is known and the
-  /// content on disk is the master (as speced with document content ownership).
+  /// content on disk is the main (as speced with document content ownership).
   ///
   /// The version number of a document will increase after each change,
   /// including undo/redo. The number doesn't need to be consecutive.
   ///
   /// clangd extension: versions are optional, and synthesized if missing.
   llvm::Optional<std::int64_t> version;
 };
 llvm::json::Value toJSON(const VersionedTextDocumentIdentifier &);

clang-tools-extra/test/modularize/SubModule2.h

-// SubModule2.h - Master header with same name as directory.
+// SubModule2.h - Main header with same name as directory.
 #include "SubModule2/Header3.h"
 #include "SubModule2/Header4.h"