Merge pull request #15026 from dancek/silver-searcher-alias-ag

silver-searcher: add alias "ag"

pkgs/top-level/all-packages.nix

···
   silc_server = callPackage ../servers/silc-server { };
 
   silver-searcher = callPackage ../tools/text/silver-searcher { };
+  ag = self.silver-searcher;
 
   simplescreenrecorder = callPackage ../applications/video/simplescreenrecorder { };