Fix modules link

Author: Grinnz

doc/Language/modules.pod6

@@ -21,7 +21,7 @@ files in a namespace.
 
 =head2 Looking for and installing modules.
 
-L<C<zef>|https://github.com/ugexe/zef> is the application using for installing modules in Perl 6. Modules are listed in L<the Perl 6 ecosystem|https://modules.perl.org> and can be searched there or from the command line using C<zef search>
+L<C<zef>|https://github.com/ugexe/zef> is the application using for installing modules in Perl 6. Modules are listed in L<the Perl 6 ecosystem|https://modules.perl6.org> and can be searched there or from the command line using C<zef search>
 
 =for code :lang<shell>
     zef search WWW