TLDR: This greatly increases the flexibility of vim modeline detection
to manually set the language of a file.
In vim there are two forms of modelines:
[text]{white}{vi:|vim:|ex:}[white]{options}
examples: 'vim: syntax=perl', 'ex: filetype=ruby'
-and-
[text]{white}{vi:|vim:|Vim:|ex:}[white]se[t] {options}:[text]
examples: 'vim set syntax=perl:', 'Vim: se ft=ruby:'
As you can see, there are many combinations. These changes should allow
most combinations to be used. The two most important additions are the
use of the keyword 'syntax', as well as the addition of the first form
(you now no longer need to use the keyword 'set' with a colon at the end).
The use of first form with 'syntax' is very, very common across GitHub:
https://github.com/search?l=ruby&q=vim%3A+syntax%3D&ref=searchresults&type=Code&utf8=%E2%9C%93
This change allows the filetype/language to be retrieved from more complex vim modelines. The current regex strictly allows a set line which contains only the filetype/ft parameter and nothing else
