Document other `{gridpattern}` patterns in a vignette

[trevorld]

Undocumented {gridpattern} patterns

• [ ] fill
• [ ] text

Original comment

• The "text" pattern seems to be the only {gridpattern} builtin pattern--hence supported by {ggpattern}--not included in a {ggpattern} vignette
• Because I just implemented a minimum-viable-product and I haven't gone to the effort of implementing https://github.com/trevorld/gridpattern/issues/49 it doesn't quite match the parameterization of the other "geometry" patterns...
• Maybe wait until we also have a https://github.com/trevorld/gridpattern/issues/55

[trevorld]

• {gridpattern} also has a new (trivial) "fill" pattern