doc: fix some minor issues (links, order, shortcut)

- [x] Add shortcut (`Ctrl+,`) for Setting dialog on the doc
- [x] Add `Editor Watcher Timeout` and `Editor Options`
- [x] Rearange level of titles and order of links

docs/WebUI/settings.md

@@ -1,5 +1,14 @@
 # Settings
 
+Via the menu or <kbd>Ctrl</kbd> + <kbd>,</kbd> (or <kbd>Meta</kbd> + <kbd>,</kbd> in the case of a Mac) you can open the Setting dialog.
+
+## Theme
+
+_The sun is too bright? You live on the dark side or only in the basement?_
+Choose between the `dark` and `light` theme.
+
+![theme](https://raw.githubusercontent.com/plantuml/plantuml-server/master/docs/WebUI/gifs/settings-theme.gif)
+
 ## Rendering Type
 
 You want always to work and see only the SVG version? Not Problem.  
@@ -7,9 +16,23 @@ Choose the rendering type you want to see.
 
 ![rendering-type](https://raw.githubusercontent.com/plantuml/plantuml-server/master/docs/WebUI/gifs/settings-rendering-type.gif)
 
-## Theme
+## Editor Watcher Timeout
 
-The sun is too bright? You live on the dark side or only in the basement?  
-Choose between the `dark` and `light` theme.
+You can change the Editor Watcher Timeout, by default it is `500 ms`.
 
-![theme](https://raw.githubusercontent.com/plantuml/plantuml-server/master/docs/WebUI/gifs/settings-theme.gif)
+
+## Editor Options
+
+You can change the options of the editor:
+
+```yaml
+{
+  automaticLayout: true,
+  fixedOverflowWidgets: true,
+  minimap: { enabled: false },
+  scrollbar: { alwaysConsumeMouseWheel: false },
+  scrollBeyondLastLine: false,
+  tabSize: 2,
+  theme: "vs",  // "vs-dark"
+}
+```