Better document context option and expected route

Swagger did not render <> so use {}.

Author: brechtvl

modules/structs/miscellaneous.go

@@ -25,7 +25,8 @@ type MarkupOption struct {
 	//
 	// in: body
 	Mode string
-	// Context to render
+	// URL path for rendering issue, media and file links
+	// Expected format: {user}/{repo}/src/{branch, commit, tag}/{identifier}/{filepath}
 	//
 	// in: body
 	Context string
@@ -53,7 +54,8 @@ type MarkdownOption struct {
 	//
 	// in: body
 	Mode string
-	// Context to render
+	// URL path for rendering issue, media and file links
+	// Expected format: {user}/{repo}/src/{branch, commit, tag}/{identifier}/{filepath}
 	//
 	// in: body
 	Context string

routers/common/markup.go

@@ -72,6 +72,7 @@ func RenderMarkup(ctx *context.Base, repo *context.Repository, mode, text, urlPr
 	}
 
 	// Parse branch path and tree path, for correct media links.
+	// The expected route is "{user}/{repo}/src/{branch, commit, tag]/{identifier}"
 	urlElements := strings.Split(strings.TrimPrefix(urlPrefix, setting.AppURL), "/")
 	if len(urlElements) >= 5 && urlElements[2] == "src" {
 		links = markup.Links{