Avoid svg xml in locale strings

assets/javascripts/discourse/connectors/user-summary-stat/solved-count.hbs

@@ -1,3 +1,3 @@
 {{#link-to 'userActivity.solved'}}
-  {{user-stat value=model.solved_count label="solved.solution_summary"}}
+  {{user-stat value=model.solved_count label="solved.solution_summary" icon="check-square"}}
 {{/link-to}}

assets/javascripts/discourse/initializers/extend-for-solved-button.js.es6

@@ -6,6 +6,7 @@ import { withPluginApi } from "discourse/lib/plugin-api";
 import { ajax } from "discourse/lib/ajax";
 import PostCooked from "discourse/widgets/post-cooked";
 import { formatUsername } from "discourse/lib/utilities";
+import { iconHTML } from "discourse-common/lib/icon-library";
 
 function clearAccepted(topic) {
   const posts = topic.get("postStream.posts");
@@ -201,6 +202,7 @@ export default {
         }
 
         return I18n.t("solved.accepted_html", {
+          icon: iconHTML('check-square'),
           username_lower: username.toLowerCase(),
           username: formatUsername(username),
           post_path: this.get("url") + "/" + postNumber,