Add tips about very basis of Vim editor (through git)

[rmarquis]

Through the usage of git, the user might come accross Vim or Nano, especially on WSL2.

Add a small tips info box giving the bare minimal, survival vim kit:

• esc for 'normal' mode, i for insert
• :w for write, :q for quit, :wq for both, :q! to quit without saving.

Do the same for Nano (^O, ^X for write and quit).