Add Pygments detection

This can be tested on the [official website](http://pygments.org/)
or on [this blog]( https://dustri.org/b/ )

src/apps.json

@@ -5811,6 +5811,14 @@
 			"icon": "Pure CSS.png",
 			"website": "purecss.io"
 		},
+		"Pygments": {
+			"cats": [
+				19
+			],
+			"html": "<link[^>]+pygments.css[\"']",
+			"icon": "pygments.png",
+			"website": "pygments.org"
+		},
 		"PyroCMS": {
 			"cats": [
 				1