reword error messages

locales/en-US.json

@@ -472,5 +472,5 @@
     "crash_page_read_the_faq": "read the <a href=\"`x`\">Frequently Asked Questions (FAQ)</a>",
     "crash_page_search_issue": "searched for <a href=\"`x`\">existing issues on GitHub</a>",
     "crash_page_report_issue": "If none of the above helped, please <a href=\"`x`\">open a new issue on GitHub</a> (preferably in English) and include the following text in your message (do NOT translate that text):",
-    "video_not_exist_in_playlist": "The video requested doesn't exist in the playlist. Click  <a href=\"`x`\">here</a> for the playlist home page."
+    "error_video_not_in_playlist": "The requested video doesn't exist in this playlist. <a href=\"`x`\">Click here for the playlist home page.</a>"
 }

src/invidious/routes/embed.cr

@@ -10,7 +10,7 @@ module Invidious::Routes::Embed
         videos = get_playlist_videos(playlist, offset: offset)
         if videos.empty?
           url = "/playlist?list=#{plid}"
-          raise NotFoundException.new(translate(locale, "video_not_exist_in_playlist", url))
+          raise NotFoundException.new(translate(locale, "error_video_not_in_playlist", url))
         end
       rescue ex : NotFoundException
         return error_template(404, ex)
@@ -70,7 +70,7 @@ module Invidious::Routes::Embed
           videos = get_playlist_videos(playlist, offset: offset)
           if videos.empty?
             url = "/playlist?list=#{plid}"
-            raise NotFoundException.new(translate(locale, "video_not_exist_in_playlist", url))
+            raise NotFoundException.new(translate(locale, "error_video_not_in_playlist", url))
           end
         rescue ex : NotFoundException
           return error_template(404, ex)