docs: fix minor typos and improve phrasing in README.md

[sakshisharma753]

Hi @Bimbok!

I noticed a couple of minor grammatical and typographical inconsistencies while reading through the project documentation:

1. Corrected a trailing "then vi" phrasing under the Controls section to "or vi".
2. Changed the randomly capitalized word "Workflow" to lowercase in the Contributing section.

These edits have been made to smooth out the reading flow of the file without changing any of your core markdown configurations or custom HTML alignment blocks.

Thank you for this awesome file manager project!