appview/pages/markup: do not render mentions in titles/descriptions

Signed-off-by: oppiliappan <[e-mail]>

appview/pages/funcmap.go

···
 	"github.com/bluesky-social/indigo/atproto/syntax"
 	"github.com/dustin/go-humanize"
 	"github.com/go-enry/go-enry/v2"
+	"github.com/yuin/goldmark"
 	"tangled.org/core/appview/filetree"
 	"tangled.org/core/appview/pages/markup"
 	"tangled.org/core/crypto"
···
 		},
 		"description": func(text string) template.HTML {
 			p.rctx.RendererType = markup.RendererTypeDefault
-			htmlString := p.rctx.RenderMarkdown(text)
+			htmlString := p.rctx.RenderMarkdownWith(text, goldmark.New())
 			sanitized := p.rctx.SanitizeDescription(htmlString)
 			return template.HTML(sanitized)
 		},

appview/pages/markup/markdown.go

···
 }
 
 func (rctx *RenderContext) RenderMarkdown(source string) string {
-	md := NewMarkdown()
+	return rctx.RenderMarkdownWith(source, NewMarkdown())
+}
 
+func (rctx *RenderContext) RenderMarkdownWith(source string, md goldmark.Markdown) string {
 	if rctx != nil {
 		var transformers []util.PrioritizedValue