add [youtube] tag support

bbcode.go

@@ -61,6 +61,12 @@ func (this *BBCodeRenderer) bbcode(data string) string {
 			nil,
 		},
 
+		pregReplaceRule{
+			regexp.MustCompile(`(?si)\[youtube](.*?)\[/youtube\]`),
+			`<iframe width="560" height="315" src="https://www.youtube-nocookie.com/embed/${1}" frameborder="0" allow="autoplay; encrypted-media" allowfullscreen></iframe>`,
+			nil,
+		},
+
 		pregReplaceRule{regexp.MustCompile(`(?si)\[section=(.*?)](.*?)\[/section\]`), "", func(m []string) string {
 			return `<div class="section"><a class="sectionheader" href="javascript:;" onclick="ts(this);">` + m[1] + `</a><span style="display:none;">` + strings.TrimSpace(m[2]) + `</span></div>`
 		}},

rFormatting.go

@@ -33,6 +33,7 @@ func (this *WikiServer) routeFormatting(w http.ResponseWriter, r *http.Request)
 	content += `
 	<li>[code]fixed width[/code]</li>
 	<li>[section=header]content[/section]</li>
+	<li>[youtube]id[/youtube]</li>
 	<li>[html]raw html[/html]</li>
 </ul>`