Update calculator search provider example (linuxmint#7879)

Remove unused imports and avoid creating unnecessary objects
on each key press.

docs/search-providers-examples/calc@cinnamon.org/search_provider.js

@@ -1,33 +1,23 @@
-const Mainloop = imports.mainloop;
-const Gio = imports.gi.Gio;
-const St = imports.gi.St;
-const Util = imports.misc.util;
 const Cinnamon = imports.gi.Cinnamon;
 
 function perform_search(pattern){
-    push_results(pattern);
-}
-
-function push_results(results){
-    var default_icon_app = Cinnamon.AppSystem.get_default().lookup_app("gcalctool.desktop");
-    var pattern = results
-    var results_array = new Array();
-
-    //First Regex tests for numbers and operators, second makes sure it does not end with an operator as that is not a valid operation
-    if ((/^[0-9.+*/()-]+$/.test(pattern)) && !(/[.+*/(-]+$/.test(pattern))) {
+    /* Test for numbers and operators and make sure it does not end with
+       an operator, as that is not a valid operation */
+    if (/^[0-9.+*/()-]+[0-9\)]$/.test(pattern)) {
         let solution = 0;
         try {
             solution = eval(pattern);
         }catch(err){}
 
         let awns = (Math.round(solution * 10000) / 10000).toString();
-        if (!(awns == pattern)) {
-            results_array.push({
+        if (awns != pattern) {
+            let default_icon_app = Cinnamon.AppSystem.get_default().lookup_app("galculator.desktop");
+            let result = {
                 id: awns,
-                label: _("Solution: " + awns),
+                label: _("Solution: %s").format(awns),
                 icon_app: default_icon_app
-            });
-            send_results(results_array);
+            };
+            send_results([result]);
         }
     }
 }