During https://gerrit.wikimedia.org/r/c/mediawiki/libs/less.php/+/981308/ we found that the fromKeyword function is duplicated for unclear reasons.
I suggest we:
- Find when it was duplicated (git blame).
- If no compelling reason is apparent from that change, then remove the Less_Parser method and call the public Less_Tree_Color::fromKeyword in both places instead. We prefer this version, because that matches where it is defined in less-2.5.3.js.