Mention that llvm_report_error() does not return.

llvm-svn: 75428

llvm/include/llvm/Support/ErrorHandling.h

@@ -42,6 +42,8 @@ namespace llvm {
   /// Reports a serious error, calling any installed error handler.
   /// If no error handler is installed the default is to print the message to
   /// standard error, followed by a newline.
+  /// After the error handler is called this function will call exit(1), it 
+  /// does not return.
   void llvm_report_error(const std::string &reason) NORETURN;
 
   /// This function calls abort(), and prints the optional message to stderr.