Fix guifont config format in gtk2 & linux, see also #436 (#511)

Author: demokn

vimrcs/extended.vim

@@ -14,9 +14,9 @@ if has("mac") || has("macunix")
 elseif has("win16") || has("win32")
     set gfn=IBM\ Plex\ Mono:h14,Source\ Code\ Pro:h12,Bitstream\ Vera\ Sans\ Mono:h11
 elseif has("gui_gtk2")
-    set gfn=IBM\ Plex\ Mono:h14,:Hack\ 14,Source\ Code\ Pro\ 12,Bitstream\ Vera\ Sans\ Mono\ 11
+    set gfn=IBM\ Plex\ Mono\ 14,:Hack\ 14,Source\ Code\ Pro\ 12,Bitstream\ Vera\ Sans\ Mono\ 11
 elseif has("linux")
-    set gfn=IBM\ Plex\ Mono:h14,:Hack\ 14,Source\ Code\ Pro\ 12,Bitstream\ Vera\ Sans\ Mono\ 11
+    set gfn=IBM\ Plex\ Mono\ 14,:Hack\ 14,Source\ Code\ Pro\ 12,Bitstream\ Vera\ Sans\ Mono\ 11
 elseif has("unix")
     set gfn=Monospace\ 11
 endif