feat: Add partial quoting

- If you select a portion of the comment, `Quote reply` will not only
quote that portion and not copy paste the whole text as it previously
did. This is achieved by using the `@github/quote-selection` package.
- There's preprocessing to ensure Forgejo-flavored markdown syntax is
preserved.
- e2e test added.
- Resolves #1342

tests/integration/repo_issue_title_test.go

@@ -39,7 +39,7 @@ func TestIssueTitles(t *testing.T) {
 
 		titleHTML := []string{
 			"Title",
-			`<span class="emoji" aria-label="thumbs up">👍</span>`,
+			`<span class="emoji" aria-label="thumbs up" data-alias="+1">👍</span>`,
 			`<code class="inline-code-block">code</code>`,
 		}