bootprefix: Tighten browser check to include the document global (#8423)

Deno's node emulation can run TiddlyWiki now that it supports the VM isolates API, but the window global exists in that environment, so both browser and node were being detected, causing the autoboot to trip up on nonexistent argv, as the boot was happening in the constructor right before argv was set.

Ref: https://github.com/denoland/deno/issues/19286
Ref: https://github.com/flexdinesh/browser-or-node

boot/bootprefix.js

@@ -21,7 +21,7 @@ $tw.boot = $tw.boot || Object.create(null);
 
 // Detect platforms
 if(!("browser" in $tw)) {
-	$tw.browser = typeof(window) !== "undefined" ? {} : null;
+	$tw.browser = typeof(window) !== "undefined" && typeof(document) !== "undefined" ? {} : null;
 }
 if(!("node" in $tw)) {
 	$tw.node = typeof(process) === "object" ? {} : null;