fontforge: remove obsolete comment

This was added in 07d12fbef1c ("fontforge: get rid of output hash
depending on git"), to explain the line:

export GIT="$(type -P true)".

This line was removed in e9848d11ad0 ("fontforge: 20190801 -> 20200314"),
but I forgot to remove the comment.

Fixes: e9848d11ad0 ("fontforge: 20190801 -> 20200314")

-1
-1
pkgs/tools/misc/fontforge/default.nix
··· 63 ++ lib.optional (!withGTK) "-DENABLE_X11=ON" 64 ++ lib.optional withExtras "-DENABLE_FONTFORGE_EXTRAS=ON"; 65 66 - # work-around: git isn't really used, but configuration fails without it 67 preConfigure = '' 68 # The way $version propagates to $version of .pe-scripts (https://github.com/dejavu-fonts/dejavu-fonts/blob/358190f/scripts/generate.pe#L19) 69 export SOURCE_DATE_EPOCH=$(date -d ${version} +%s)
··· 63 ++ lib.optional (!withGTK) "-DENABLE_X11=ON" 64 ++ lib.optional withExtras "-DENABLE_FONTFORGE_EXTRAS=ON"; 65 66 preConfigure = '' 67 # The way $version propagates to $version of .pe-scripts (https://github.com/dejavu-fonts/dejavu-fonts/blob/358190f/scripts/generate.pe#L19) 68 export SOURCE_DATE_EPOCH=$(date -d ${version} +%s)