links check

[Ezzat1998]

1. PEP 257
   Under the paragraph 'golden-rules' in the file document-code.ipynb (third markdown cell). i think the link PEP 257 shoud be updated to PEP 257.

2. fig 58
   Under the paragraph "workflows," in the "Git in VS Code" section of the "local commits" file, there is a link that should refer to Fig. 58, but it does not correctly.