Add keyboard shortcuts link to getting-started navigation (#5874)

* Add keyboard shortcuts link to getting-started navigation

* i18n: 🇵🇱

* yarn manage:translations

app/javascript/mastodon/locales/fi.json

@@ -7,6 +7,7 @@
   "account.followers": "Seuraajia",
   "account.follows": "Seuraa",
   "account.follows_you": "Seuraa sinua",
+  "account.hide_reblogs": "Hide boosts from @{name}",
   "account.media": "Media",
   "account.mention": "Mainitse @{name}",
   "account.moved_to": "{name} has moved to:",
@@ -16,6 +17,7 @@
   "account.report": "Report @{name}",
   "account.requested": "Odottaa hyväksyntää",
   "account.share": "Share @{name}'s profile",
+  "account.show_reblogs": "Show boosts from @{name}",
   "account.unblock": "Salli @{name}",
   "account.unblock_domain": "Unhide {domain}",
   "account.unfollow": "Lopeta seuraaminen",
@@ -132,6 +134,7 @@
   "navigation_bar.favourites": "Favourites",
   "navigation_bar.follow_requests": "Follow requests",
   "navigation_bar.info": "Extended information",
+  "navigation_bar.keyboard_shortcuts": "Keyboard shortcuts",
   "navigation_bar.logout": "Kirjaudu ulos",
   "navigation_bar.mutes": "Muted users",
   "navigation_bar.pins": "Pinned toots",