WebPositive: remove gopher from supported protocols

Goodbye sweet prince!
This hasen't worked for quite some time, Webkit uses the curl backend
currently which has no support for gopher.

Our netkit backend also never "truely" supported gopher, instead
translating pages to html with some prebuild styles, those also don't
use the CSS system colors, for lack of existence back then.

Change-Id: I5d5098db9512bb22cde8c17fa1553637b30ae65b
Reviewed-on: https://review.haiku-os.org/c/haiku/+/8938
Reviewed-by: waddlesplash <[email protected]>
Tested-by: Commit checker robot <[email protected]>

src/apps/webpositive/WebPositive.rdef

@@ -24,7 +24,6 @@ resource file_types message {
 	"types" = "application/xhtml+xml",
 	"types" = "application/x-vnd.Be.URL.file",
 	"types" = "application/x-vnd.Be.URL.ftp",
-	"types" = "application/x-vnd.Be.URL.gopher",
 	"types" = "application/x-vnd.Be.URL.http",
 	"types" = "application/x-vnd.Be.URL.https"
 };