modules/lsp/servers: simplify activate default

The default for `lsp.servers.<name>.activate` used to be conditional on
whether `name == "*"`. This is leftover from before the * server was
moved to its own `global-server.nix` module and can now be removed.

(cherry picked from commit 753f7640d6)

modules/lsp/servers/server.nix

@@ -36,10 +36,7 @@ in
       description = ''
         Whether to call `vim.lsp.enable()` for ${displayName}.
       '';
-      default = config.name != "*";
-      defaultText = lib.literalMD ''
-        `true`, unless the server's `name` is `*`
-      '';
+      default = true;
       example = false;
     };