Add a comment to clarify the contract for LLVMGetErrorMessage in the c-bindings

for Error.

llvm-svn: 343394

llvm/include/llvm-c/Error.h

@@ -47,6 +47,8 @@ void LLVMConsumeError(LLVMErrorRef Err);
 /**
  * Returns the given string's error message. This operation consumes the error,
  * and the given LLVMErrorRef value is not usable once this call returns.
+ * The caller is responsible for disposing of the string by calling
+ * LLVMDisposeErrorMessage.
  */
 char *LLVMGetErrorMessage(LLVMErrorRef Err);