ask for a pr when licenses are missing

templates/_asset_fields.phtml

@@ -71,7 +71,7 @@ $_asset_values = array_merge([
                 </option>
             <?php } ?>
         </select>
-        <span class="help-block">The license under which the asset is available. Check <a href="https://opensource.org/licenses">opensource.org</a> for a more detailed description of each. In case an OSI-approved license you are using is missing, you might <a href="https://github.com/godotengine/asset-library/issues">open an issue</a> about it.</span>
+        <span class="help-block">The license under which the asset is available. Check <a href="https://opensource.org/licenses">opensource.org</a> for a more detailed description of each. In case an OSI-approved license you are using is missing, please add the license in <a href="https://github.com/godotengine/godot-asset-library/blob/master/src/constants.php">this file</a> and open a pull request.</span>
         <span class="help-block"><strong>Note:</strong> The license you specify here should also be included in the repository you are submitting under a standard name, such as LICENSE or LICENSE.md</span>
     </div>
 </div>