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 Text variant that support "density" instead of "size" gridpattern#49 it doesn't quite match the parameterization of the other "geometry" patterns...
• Maybe wait until we also have a 'dungeon' pattern? gridpattern#55

[trevorld]

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