[feature] Parse content warning to HTML, serialize via client API as plaintext (#3876)

* [feature] Parse content warning as HTML, serialize via API to plaintext

* tidy up some cruft

* whoops

* oops

* i'm da joker baybee

* clemency muy lorde

* rename some of the text functions for clarity

* jiggle the opts

* fiddle de deee

* hopefully the last test fix i ever have to do in my beautiful life

internal/api/client/statuses/statusfave_test.go

@@ -103,7 +103,7 @@ func (suite *StatusFaveTestSuite) TestPostFave() {
   },
   "bookmarked": false,
   "card": null,
-  "content": "🐕🐕🐕🐕🐕",
+  "content": "<p>🐕🐕🐕🐕🐕</p>",
   "content_type": "text/plain",
   "created_at": "right the hell just now babyee",
   "edited_at": null,