Remove suffix from Icon key in desktop entries
Suffixes, like .png, are not part of the specification. Although many
ports like misc/xfce4-appfinder have implemented workarounds for it,
ports like x11/rofi are missing icons due to a suffix being present in the
Icon key.
References:
- https://specifications.freedesktop.org/desktop-entry-spec/latest/ar01s06.html
- https://specifications.freedesktop.org/icon-theme-spec/icon-theme-spec-latest.html#icon_lookup
Approved by: portmgr (blanket, runtime fixes)