Fix under-indented comments.

def fix_e112(self, result):
        """Fix under-indented comments."""
        line_index = result['line'] - 1
        target = self.source[line_index]

        if not target.lstrip().startswith('#'):
            # Don't screw with invalid syntax.
            return []

        self.source[line_index] = self.indent_word + target