feh(1): --theme: Add note that the default theme is feh

- see

.Sx THEMES CONFIG SYNTAX

for more info.  Note that options from the theme file always override

commandline options.

commandline options.  The theme can also be set via the program name

.Pq e.g. with symlinks ,

so by default

.Nm

will look for a

.Qq Nm

theme.

.

.It Cm -t , --thumbnails

Same as Index mode, but the thumbnails are clickable image launchers.