[clangd] NFC: Update Serialization routine documentation

[kbobyrev]

Summary

According to new implementation, readIndexFile can also process YAML symbol collections. Also, it might make sense to use Doxygen comments here so that the Doxygen documentation would include short description of each function.

[sammccall]

The wording change is in D52531.

[kbobyrev]

In D52534#1246190, @sammccall wrote:

The wording change is in D52531.

Oh, I didn't see that one. Thanks!

[kbobyrev]

This is no longer needed then.

clang-tools-extra/clangd/index/Serialization.h

 namespace clang {
 namespace clangd {
 
 enum class IndexFileFormat {
   RIFF, // Versioned binary format, suitable for production use.
   YAML, // Human-readable format, suitable for experiments and debugging.
 };
 
-// Holds the contents of an index file that was read.
+/// Holds the contents of an index file that was read.
 struct IndexFileIn {
   llvm::Optional<SymbolSlab> Symbols;
 };
-// Parse an index file. The input must be a RIFF container chunk.
+/// Parse an index file. The input must be a RIFF container chunk or YAML symbol
+/// collection.
 llvm::Expected<IndexFileIn> readIndexFile(llvm::StringRef);
 
-// Specifies the contents of an index file to be written.
+/// Specifies the contents of an index file to be written.
 struct IndexFileOut {
   const SymbolSlab *Symbols;
   // TODO: Support serializing symbol occurrences.
   // TODO: Support serializing Dex posting lists.
   IndexFileFormat Format = IndexFileFormat::RIFF;
 
   IndexFileOut() = default;
   IndexFileOut(const IndexFileIn &I)
       : Symbols(I.Symbols ? I.Symbols.getPointer() : nullptr) {}
 };
-// Serializes an index file.
+/// Serializes an index file.
 llvm::raw_ostream &operator<<(llvm::raw_ostream &OS, const IndexFileOut &O);
 
 std::string toYAML(const Symbol &);
-// Returned symbol is backed by the YAML input.
+/// Returned symbol is backed by the YAML input.
 // FIXME: this is only needed for IndexerMain, find a better solution.
 llvm::Expected<Symbol> symbolFromYAML(llvm::yaml::Input &);
 
-// Build an in-memory static index from an index file.
-// The size should be relatively small, so data can be managed in memory.
+/// Build an in-memory static index from an index file.
+/// The size should be relatively small, so data can be managed in memory.
 std::unique_ptr<SymbolIndex> loadIndex(llvm::StringRef Filename,
                                        llvm::ArrayRef<std::string> URISchemes,
                                        bool UseDex = true);
 
 } // namespace clangd
 } // namespace clang
 
 #endif