phpstan: Ignore warnings on missing return statement.

While some of these may be fixable without too much hassle, quite a few
of them will possibly require architectural restructuring. We should
revisit these, but let's silence them for now.

phpstan.neon.dist

@@ -7,3 +7,5 @@ parameters:
 		- Zotlabs
 	scanDirectories:
 		- library
+	ignoreErrors:
+		- '#Method [\w:()_\\]+ should return (object|string) but return statement is missing.#'