The following pattern is inefficient: `r'([ \f\t]*)([=:]*)([ \f\t]*)(.*(?<!\\)(?:\\{2})*)(\\)(?!\\)$` [https://github.com/pygments/pygments/blob/master/pygments/lexers/configs.py#L141](https://github.com/pygments/pygments/blob/master/pygments/lexers/configs.py#L141)
The following pattern is inefficient:
r'([ \f\t]*)([=:]*)([ \f\t]*)(.*(?<!\\)(?:\\{2})*)(\\)(?!\\)$https://github.com/pygments/pygments/blob/master/pygments/lexers/configs.py#L141