build(electron): Add "Office" as category for Desktop file

as per https://specifications.freedesktop.org/menu-spec/latest/category-registry.html

checked with other NoteTaking apps and they all (e.g. Obsidian, Joplin) use "Office" as main category as well, which makes sense here

forge.config.cjs

@@ -7,6 +7,7 @@ const extraResourcesForPlatform = getExtraResourcesForPlatform();
 const baseLinuxMakerConfigOptions = {
   icon: "./images/app-icons/png/128x128.png",
   desktopTemplate: path.resolve("./bin/electron-forge/desktop.ejs"),
+  categories: ["Office", "Utility"]
 };
 
 module.exports = {