Change markdown rendering from blackfriday to goldmark (#9533)

* Move to goldmark

Markdown rendering moved from blackfriday to the goldmark.

Multiple subtle changes required to the goldmark extensions to keep
current rendering and defaults.

Can go further with goldmark linkify and have this work within markdown
rendering making the link processor unnecessary.

Need to think about how to go about allowing extensions - at present it
seems that these would be hard to do without recompilation.

* linter fixes

Co-authored-by: Lauris BH <lauris@nix.lv>

routers/api/v1/misc/markdown_test.go

@@ -69,7 +69,6 @@ func TestAPI_RenderGFM(t *testing.T) {
 - Bezier widget (by @r-lyeh) https://github.com/ocornut/imgui/issues/786`,
 		// rendered
 		`<p>Wiki! Enjoy :)</p>
-
 <ul>
 <li><a href="` + AppSubURL + `wiki/Links" rel="nofollow">Links, Language bindings, Engine bindings</a></li>
 <li><a href="` + AppSubURL + `wiki/Tips" rel="nofollow">Tips</a></li>
@@ -88,13 +87,9 @@ Here are some links to the most important topics. You can find the full list of
 `,
 		// rendered
 		`<h2 id="user-content-what-is-wine-staging">What is Wine Staging?</h2>
-
 <p><strong>Wine Staging</strong> on website <a href="http://wine-staging.com" rel="nofollow">wine-staging.com</a>.</p>
-
 <h2 id="user-content-quick-links">Quick Links</h2>
-
 <p>Here are some links to the most important topics. You can find the full list of pages at the sidebar.</p>
-
 <p><a href="` + AppSubURL + `wiki/Configuration" rel="nofollow">Configuration</a>
 <a href="` + AppSubURL + `wiki/raw/images/icon-bug.png" rel="nofollow"><img src="` + AppSubURL + `wiki/raw/images/icon-bug.png" title="icon-bug.png" alt="images/icon-bug.png"/></a></p>
 `,