Remove obsolete Group tag

References: https://fedoraproject.org/wiki/Changes/Remove_Group_Tag

gambit-c.spec

@@ -18,7 +18,6 @@ Version:        4.8.9
 Release:        1%{?dist}
 Summary:        Scheme programming system
 
-Group:          Development/Languages
 License:        ASL 2.0 or LGPLv2
 URL:            http://gambitscheme.org/
 %global _dirname gambit-v%(echo %{version} | sed -e 's/\\./_/g')-devel
@@ -48,7 +47,6 @@ numbers), and complex numbers.
 
 %package        doc
 Summary:        Documentation for %{name}
-Group:          Documentation
 
 BuildArch:      noarch
 Requires:       %{name} = %{version}-%{release}