[clangd] NFC: fix clang-tidy warnings.

Most are about llvm code style violation (found via
readability-identifier-naming check).

llvm-svn: 352205
diff --git a/clang-tools-extra/clangd/SourceCode.h b/clang-tools-extra/clangd/SourceCode.h
index a3dbc7a..7c8499d 100644
--- a/clang-tools-extra/clangd/SourceCode.h
+++ b/clang-tools-extra/clangd/SourceCode.h
@@ -90,7 +90,7 @@
 llvm::Optional<std::string> getCanonicalPath(const FileEntry *F,
                                              const SourceManager &SourceMgr);
 
-bool IsRangeConsecutive(const Range &Left, const Range &Right);
+bool isRangeConsecutive(const Range &Left, const Range &Right);
 } // namespace clangd
 } // namespace clang
 #endif