devtools/hackdoc: serve JS with correct mimetype

This allows us to serve rich content from hackdoc, eg. hbj11's
webflaser.

Change-Id: Ife83888d864db0b2eddf3a50b0129be0172aad8a

devtools/hackdoc/markdown.go

@@ -151,7 +151,14 @@ func (r *request) handleFile(path string, cfg *config.Config) {
 	}
 
 	// Just serve the file.
-	mime := mimetype.Detect(data)
-	r.w.Header().Set("Content-Type", mime.String())
+	var mime string
+	if strings.HasSuffix(path, ".js") {
+		// Force .js to always be the correct MIME type.
+		mime = "text/javascript"
+	} else {
+		// Otherwise, use magic to detect type.
+		mime = mimetype.Detect(data).String()
+	}
+	r.w.Header().Set("Content-Type", mime)
 	r.w.Write(data)
 }

devtools/kube/hackdoc.libsonnet

@@ -3,7 +3,7 @@ local kube = import "../../kube/kube.libsonnet";
 
 {
     cfg:: {
-        image: "registry.k0.hswaw.net/q3k/hackdoc:315532800-a415ced850425a195f96b331f57cd78f15e622d9",
+        image: "registry.k0.hswaw.net/q3k/hackdoc:315532800-f4d02581f60b18a8635d026079ed67039cdc45e6",
         publicFQDN: error "public FQDN must be set",
     },