Add --search to manpage

Fixes: GNOME/epiphany#1256
3 jobs for fix-search-in-manpage in 20 minutes (queued for 1 second)
Status Job ID Name Coverage
  .Pre
passed #795170
check-code-style

00:02:30

 
  Test
passed #795171
flatpak
flatpak

00:17:30

passed #795172
flatpak
flatpak scanbuild

00:07:04