Rewrite --word-diff-regex to be more intelligent
Rewrite --word-diff-regex to be more intelligent

The old character-by-character regex worked well for non-alphanumeric
character diffs. However, this behavior had the effect of making diffs
between alphanumeric characters much more difficult to read. Therefore,
only perform a character-wise diff if the character is not alphanumeric.

caleb531/dotfiles,caleb531/dotfiles,caleb531/dotfiles,caleb531/dotfiles