SpanClass finetuning

[asillye]

This is a minor glitch only.. when using SpanClasses the coloring has two issues. Consider:
span class Keyword = ( ['a'..'z', '_']['a'..'z', '_', '-']+ ) - "disable";
syntax OptionalDisable = DM=(DisableKeyword sm)?;
[SpanClass(SpanWarning)]
syntax DisableKeyword = "disable";

We set SpanWarning to a different color and yellow background color. The purpose is to make the 'disable' keyword stand out.

Problem 1: we had to subtract the disable word from keywords, otherwise the SpanClass on the DisableKeyword will not be applied. This is a matter of taste, however it would be nice, if the explicit SpanWarning on the DisableKeyword syntax element would have priority compared to the generic Keyword one.

Problem 2: with the above setup the sm space after the disable will get highlighted to yellow.
e.g. disable scenario [XY] {... } will highlight the space between disable and scenario while the spanclass is only defined for DisableKeyword.