[clangd][NFC] Delete dead code

Author: kadircet

clang-tools-extra/clangd/IncludeCleaner.h

@@ -62,15 +62,6 @@ issueIncludeCleanerDiagnostics(ParsedAST &AST, llvm::StringRef Code,
                                const ThreadsafeFS &TFS,
                                HeaderFilter IgnoreHeader = {});
 
-/// Affects whether standard library includes should be considered for
-/// removal. This is off by default for now due to implementation limitations:
-/// - macros are not tracked
-/// - symbol names without a unique associated header are not tracked
-/// - references to std-namespaced C types are not properly tracked:
-///   instead of std::size_t -> <cstddef> we see ::size_t -> <stddef.h>
-/// FIXME: remove this hack once the implementation is good enough.
-void setIncludeCleanerAnalyzesStdlib(bool B);
-
 /// Converts the clangd include representation to include-cleaner
 /// include representation.
 include_cleaner::Includes convertIncludes(const ParsedAST &);