[bugfix] html escape special characters in text instead of totally removing them (#719)

* remove minify dependency

* tidy up some tests

* remove pre + postformat funcs

* rework sanitization + formatting

* update tests

* add some more markdown tests

internal/text/minify.go

@@ -1,39 +0,0 @@
-/*
-   GoToSocial
-   Copyright (C) 2021-2022 GoToSocial Authors admin@gotosocial.org
-
-   This program is free software: you can redistribute it and/or modify
-   it under the terms of the GNU Affero General Public License as published by
-   the Free Software Foundation, either version 3 of the License, or
-   (at your option) any later version.
-
-   This program is distributed in the hope that it will be useful,
-   but WITHOUT ANY WARRANTY; without even the implied warranty of
-   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-   GNU Affero General Public License for more details.
-
-   You should have received a copy of the GNU Affero General Public License
-   along with this program.  If not, see <http://www.gnu.org/licenses/>.
-*/
-
-package text
-
-import (
-	"github.com/tdewolff/minify/v2"
-	"github.com/tdewolff/minify/v2/html"
-)
-
-var m *minify.M
-
-// MinifyHTML runs html through a minifier, reducing it in size.
-func MinifyHTML(in string) (string, error) {
-	if m == nil {
-		m = minify.New()
-		m.Add("text/html", &html.Minifier{
-			KeepQuotes:       true,
-			KeepEndTags:      true,
-			KeepDocumentTags: true,
-		})
-	}
-	return m.String("text/html", in)
-}