edited docs to prefer f-strings, then str.format(), and remove %-interpolation
additional ad-hoc documentation fixes, as opportunities seen:
- replace Built-In Function (BIF) "min" variable with "mins"
- prefer BIF str(var) over "%s" % var
- reformat some code examples to clarify multiple args passed to functions
- change some single-quote strings to double-quotes for consistency
- fix mismatched parens
misc edits:
- add .vscode/ to gitignore
