KaTeX: Fix problem running under TiddlyDesktop as a wikifolder

Fixes https://github.com/Jermolene/TiddlyDesktop/issues/124 (the problem over there is that TiddlyWiki running as a wiki folder in TiddlyDesktop reports itself as running both under Node and the browser, and the previous test was wrongly choosing the fakedom)

plugins/tiddlywiki/katex/files/tiddlywiki.files

@@ -25,7 +25,7 @@
 				"module-type": "library"
 			},
 			"prefix": "(function(document) {\n",
-			"suffix": "\n})($tw.node ? $tw.fakeDocument : window.document)\n"
+			"suffix": "\n})(!$tw.browser ? $tw.fakeDocument : window.document)\n"
 		}
 	]
 }