This PR fixes an inconsistency between isWritable and getWriteInfo in the ReflectionExtractor.

isWritable() correctly found mutators for snake_case properties because it had a fallback mechanism:

1. Check for setSnakeProperty
2. If not found, check for setSnake_method

The getWriteInfo() method only checked for the camelCase version (setSnakeProperty)

This caused isWritable(..., 'snake_method') to return true, while getWriteInfo(..., 'snake_method') would incorrectly return TYPE_NONE.