style(angular.bootstrap): remove unnecessary capital letters

src/Angular.js

@@ -1623,7 +1623,7 @@ function bootstrap(element, modules, config) {
       //Encode angle brackets to prevent input from being sanitized to empty string #8683
       throw ngMinErr(
           'btstrpd',
-          "App Already Bootstrapped with this Element '{0}'",
+          "App already bootstrapped with this element '{0}'",
           tag.replace(/</,'&lt;').replace(/>/,'&gt;'));
     }