message: [trivial] fix MLIRContext::registerDiagnosticHandler documentation
  The documentation for MLIRContext::registerDiagnosticHandler describing the
  arguments of the diagnostic handler is inconsistent with the code.  It also
  mentions LLVM context rather than MLIR context, likely a typo.  Fix both
  issues.
diff: @@ -397,9 +397,9 @@ MLIRContext::~MLIRContext() {}
  // Diagnostic Handlers
  //===----------------------------------------------------------------------===//
  -/// Register an issue handler with this LLVM context. The issue handler is
  -/// passed location information if present (nullptr if not) along with a
  -/// message and a boolean that indicates whether this is an error or warning.
  +/// Register an issue handler with this MLIR context. The issue handler is
  +/// passed location information along with a message and a DiagnosticKind enum
  +/// value that indicates the type of the diagnostic (e.g., Warning, Error).
  void MLIRContext::registerDiagnosticHandler(
  const DiagnosticHandlerTy &handler) {
  getImpl().diagnosticHandler = handler;
  