Minor improvement to 'setErrMsg'

1. code like `char msg[] = "xxxxxx"` unnecessarily copied the string to stack, changed to `const char* msg = "xxxxxx"`.
2. the 2rd argument of `setErrMsg` is changed from `char*` to `const char*`.
3. the 3rd argument of `setErrMsg` is removed as `strncpy` stops copying at the end of source string.

src/client/src/tscParseInsert.c

@@ -348,7 +348,7 @@ int32_t tsParseOneColumnData(SSchema* pSchema, char* value, int valuelen, char*
 
 // todo merge the error msg function with tSQLParser
 static void setErrMsg(char* msg, char* sql) {
-  char          msgFormat[] = "near \"%s\" syntax error";
+  const char*   msgFormat = "near \"%s\" syntax error";
   const int32_t BACKWARD_CHAR_STEP = 15;
 
   // only extract part of sql string,avoid too long sql string cause stack over flow