Register 12 new JSON filenames/extensions (#4053)

Added:
* .avsc
* .gltf
* .htmlhintrc
* .jscsrc
* .jslintrc
* .jsonl
* .tern-config
* .tern-project
* .tfstate
* .tfstate.backup
* .webapp
* .webmanifest

samples/JSON/manifest.webmanifest

@@ -0,0 +1,56 @@
+{
+	"short_name": "CC Splitter",
+	"name": "Credit Card Splitter",
+	"start_url": "./index.html",
+	"display": "standalone",
+	"theme_color": "#000000",
+	"background_color": "#ffffff",
+	"lang": "en-GB",
+	"icons": [
+		{
+			"src": "logo-16.png",
+			"sizes": "16x16",
+			"type": "image/png"
+		},
+		{
+			"src": "logo-36.png",
+			"sizes": "36x36",
+			"type": "image/png"
+		},
+		{
+			"src": "logo-48.png",
+			"sizes": "48x48",
+			"type": "image/png"
+		},
+		{
+			"src": "logo-72.png",
+			"sizes": "72x72",
+			"type": "image/png"
+		},
+		{
+			"src": "logo-96.png",
+			"sizes": "96x96",
+			"type": "image/png"
+		},
+		{
+			"src": "logo-144.png",
+			"sizes": "144x144",
+			"type": "image/png"
+		},
+		{
+			"src": "logo-192.png",
+			"sizes": "192x192",
+			"type": "image/png"
+		},
+		{
+			"src": "logo-250.png",
+			"sizes": "250x250",
+			"type": "image/png"
+		},
+		{
+			"src": "logo-512.png",
+			"sizes": "512x512",
+			"type": "image/png"
+		}
+	]
+}