fix: will-mount should return a state

Resolved #713

src/main/frontend/components/diff.cljs

@@ -169,7 +169,8 @@
                       "Install Logseq on GitHub"
                       :href (str "https://github.com/apps/" config/github-app-name "/installations/new"))]
                    :error
-                   false)))))))))
+                   false))))))))
+     state)
    :will-unmount
    (fn [state]
      (reset! diffs nil)