Add a tooltip explaining what a locked account is (#9403)

* create a title tooltip explaining what a locked account is

* improve phrasing

* minor phrasing fix to unify default and english

app/javascript/mastodon/locales/en.json

@@ -17,6 +17,7 @@
   "account.follows_you": "Follows you",
   "account.hide_reblogs": "Hide boosts from @{name}",
   "account.link_verified_on": "Ownership of this link was checked on {date}",
+  "account.locked_info": "This account privacy status is set to locked. The owner manually reviews who can follow them.",
   "account.media": "Media",
   "account.mention": "Mention @{name}",
   "account.moved_to": "{name} has moved to:",

app/javascript/mastodon/locales/pl.json

@@ -17,6 +17,7 @@
   "account.follows_you": "Śledzi Cię",
   "account.hide_reblogs": "Ukryj podbicia od @{name}",
   "account.link_verified_on": "Własność tego odnośnika została potwierdzona {date}",
+  "account.locked_info": "To konto jest prywatne. Właściciel ręcznie wybiera kto może go śledzić.",
   "account.media": "Zawartość multimedialna",
   "account.mention": "Wspomnij o @{name}",
   "account.moved_to": "{name} przeniósł(-osła) się do:",