dot-str: edge label, when available, takes precedence over weight.
Improved docstring for dot-str.
Corrected misplaced docstrings (found by eastwood).
Corrected misplaced type hint (caught by eastwood).
Merge pull request #37 from fmjrey/eastwood

Corrected misplaced docstrings and type hints (found by eastwood).
Merge pull request #32 from fmjrey/dot-str-label-over-weight

dot-str: edge label, when available, takes precedence over weight.