Internationalized "Go to a randomly selected page"

At this point a potential issue has been revealed. Now we produce
the final HTML via 2-level template expansion

1. Render parameterized messages
2. Render the HTML template

In which templates we should use double mustache "{{}}" (HTML-escaping)
tags and where we may use triple mustache "{{{}}}" (non-escaping) tags?

src/server/response.cpp

@@ -291,6 +291,7 @@ void ContentResponse::introduce_taskbar(const std::string& lang)
     {"withlibrarybutton", m_withLibraryButton},
     {"LIBRARY_BUTTON_TEXT", t("library-button-text")},
     {"HOME_BUTTON_TEXT", t("home-button-text", {{"BOOK_TITLE", m_bookTitle}}) },
+    {"RANDOM_PAGE_BUTTON_TEXT", t("random-page-button-text") },
   };
   auto head_content = render_template(RESOURCE::templates::head_taskbar_html, data);
   m_content = prependToFirstOccurence(

static/i18n/en.json

@@ -21,4 +21,5 @@
 	, "no-search-results": "The fulltext search engine is not available for this content."
 	, "library-button-text": "Go to welcome page"
 	, "home-button-text": "Go to the main page of '{{BOOK_TITLE}}'"
+	, "random-page-button-text": "Go to a randomly selected page"
 }

static/i18n/hy.json

@@ -11,4 +11,5 @@
 	, "404-page-heading" : "Սխալ հասցե"
 	, "library-button-text": "Գրադարանի էջ"
 	, "home-button-text": "Դեպի '{{BOOK_TITLE}}'֊ի գլխավոր էջը"
+	, "random-page-button-text": "Բացել պատահական էջ"
 }

static/i18n/qqq.json

@@ -22,4 +22,5 @@
 	, "no-search-results": "Text of the error page returned when search is attempted in a book without fulltext search database"
 	, "library-button-text": "Tooltip of the button leading to the welcome page"
 	, "home-button-text": "Tooltip of the button leading to the main page of a book"
+	, "random-page-button-text": "Tooltip of the button opening a randomly selected page"
 }

static/templates/taskbar_part.html

@@ -16,7 +16,7 @@
           {{/withlibrarybutton}}
           {{#hascontent}}
           <a id="kiwix_serve_taskbar_home_button" title="{{{HOME_BUTTON_TEXT}}}" aria-label="{{{HOME_BUTTON_TEXT}}}" href="{{root}}/{{content}}/"><button>{{title}}</button></a>
-          <a id="kiwix_serve_taskbar_random_button" title="Go to a randomly selected page" aria-label="Go to a randomly selected page"
+          <a id="kiwix_serve_taskbar_random_button" title="{{{RANDOM_PAGE_BUTTON_TEXT}}}" aria-label="{{{RANDOM_PAGE_BUTTON_TEXT}}}"
             href="{{root}}/random?content={{#urlencoded}}{{{content}}}{{/urlencoded}}"><button>&#x1F3B2;</button></a>
           {{/hascontent}}
         </div>