docs: Add release notes for v4.0.0.

docs: Add release notes for v3.1.0-beta.

release: New release v3.0.0.

New beta release v2.5.0.

pdf-viewer: disable pdf-viewer window.

Disable the pdf window for now since this is broken in v3
of electron.

Fixes zulip#640.

release: 🎉 new release v2.3.82.

release: 🎉 new release v2.3.8.

server-name: Unescape server name in window menu item.

Escaping is necessary to avoid any security risk but we need
to unescape those strings in order to show them in the frontend
otherwise it will have ugly special characters.

We already escape server name in the db and unesacoe it in
the left-sidebar. This PR adds the decodeString function in
order to unescape strings in the menu items.

Fixes: zulip#554.

release: 🎉 new release v2.3.6.

release: 🎉 new release v2.3.5.