[Bug] Parser: limiting color options leads to unclear error message

[neteler]

Describe the bug

When using the color list parser macro G_OPT_M_COLR
(e.g., see

grass/temporal/t.rast.colors/t.rast.colors.py

Line 34 in e1756b5

# %option G_OPT_M_COLR

) but desiring to reduce the selectable colors to a subset this leads to unclear warnings.

Example: The PR cited below is defining a subset of colors in options which leads to

WARNUNG: Bug in UI description. Option 'aspect' in <color> does not exist
WARNUNG: Bug in UI description. Option 'aspectcolr' in <color> does not exist
...

for each color name missing from the options list. The warning is here:

grass/lib/gis/parser.c

Line 351 in 40b5982

G_warning(_("Bug in UI description. Missing module description"));

To Reproduce

See changes and discussion in
mundialis/r.geoserver#4

Expected behavior

It should be possible to use a parser macro while being able to reduce the options.

System description (please complete the following information):

• any operating system
• GRASS GIS version 8.x