[suggestion] use relative path in DIRECTORY.md

[15921483570]

when openning DIRECTORY.md in local machine, the links in it refers to https://github.com/TheAlgorithms/Python/blob/master/xxx.

it's not convinient for reading locally.

I suggest to make a new file "TOC.md", which removes "https://github.com/TheAlgorithms/Python/blob/master/" in every link.

[poyea]

This makes perfect sense! Do you know if the relative path resolution is supported by GitHub?