yaml: fix the anchor group in increaseIndentPattern

The pattern had an HTML-escaped "&" where it meant "&", so a key
followed by an anchor (foo: &anchor) never increased the indent.

extensions/yaml/language-configuration.json

@@ -29,7 +29,7 @@
 		}
 	},
 	"indentationRules": {
-		"increaseIndentPattern": "^\\s*.*(:|-) ?(&\\w+)?(\\{[^}\"']*|\\([^)\"']*)?$",
+		"increaseIndentPattern": "^\\s*.*(:|-) ?(&\\w+)?(\\{[^}\"']*|\\([^)\"']*)?$",
 		"decreaseIndentPattern": "^\\s+\\}$"
 	}
 }