Fix #110: Recognize keyframes at-rule with vendor prefixes

[clchen28]

Description of the Change

Added -webkit-keyframes, -moz-keyframes, -o-keyframes, and -ms-keyframes to begin and patterns regex for @keyframes in grammar.cson, allowing these to follow the same syntax highlighting rules as @keyframes.

Fix #110

Benefits

Applies @keyframes at-rule syntax highlighting correctly if vendor prefixes are used

Applicable Issues

#99 Add support for literally every modern CSS feature

[winstliu]

Your change can be simplified to (-(webkit|moz|o)-)?keyframes. I'll leave it to @Alhadis to decide if the vendor prefix should receive additional scopes.

[clchen28]

Ok - amended previous commit with simplified regex (-(webkit|moz|o)-)?keyframes.

[Alhadis]

Nope, no need for additional scopes. I'd make the groups non-capturing, though, to save a little extra overhead.

[clchen28]

Ok @Alhadis - I've amended the commit and updated the groups to be non-capturing,

e.g.
'begin': '(?i)(?=@(?:(?:-(?:webkit|moz|o|ms)-)?keyframes)([\\s\'"{;]|/\\*|$))'

and

'begin': '(?i)\\G(@)(?:(?:-(?:webkit|moz|o|ms)-)?keyframes)'

[Alhadis]

@50Wliu LGTM.

[winstliu]

The outside capture can be removed, so this can be simplified to be (?:-(?:webkit|moz|o|ms)-)?keyframes. Same for below.

(?i)(?=@(?:-(?:webkit|moz|o|ms)-)?keyframes([\\s\'"{;]|/\\*|$))

[clchen28]

Ok - @50Wliu per your review, I've amended the commit to remove the outer capture for the regex, e.g. (?i)(?=@(?:-(?:webkit|moz|o|ms)-)?keyframes([\\s\'"{;]|/\\*|$)) and (?i)\\G(@)(?:-(?:webkit|moz|o|ms)-)?keyframes

[winstliu]

Thanks!

[clchen28]

:D My first ever PR for FOSS! Thanks for the review.