Autocomplete: change type from 'contact' to 'person' to sync with what is expected from LDAP.

Explanation:
Alternative would be to leave type empty, as it is when contact comes form SQL source.
But this feels overly ambiguous and may cause problems in the future.

program/js/app.js

@@ -5182,7 +5182,7 @@ function rcube_webmail()
     this.set_caret_pos(this.ksearch_input, p + insert.length);
 
     if (trigger) {
-      this.triggerEvent('autocomplete_insert', { field:this.ksearch_input, insert:insert, data:this.env.contacts[id], search:this.ksearch_value, result_type:'contact' });
+      this.triggerEvent('autocomplete_insert', { field:this.ksearch_input, insert:insert, data:this.env.contacts[id], search:this.ksearch_value, result_type:'person' });
       this.compose_type_activity++;
     }
   };