False positive: ba → by/be in wgsl shaders

[bbb651]

The issue appears in iced with wgsl shaders here and here.

In general, using any sequence of r, g, b, a up to ~4 characters appears commonly in shaders with swizzling.

[epage]

As there are workarounds for this and this seems fairly specialized of a domain, I wonder if we should leave this to users to take care of.

[bbb651]

I think dealing with just the most common ones is worthwhile, e.g. ba specifically seems to be used a lot (1.4k results with a very conservative query just for shaders), because it's both the second half of rgba, and it's also used a lot for b - a with vectors (along with cb, pa, oa).