@grafana/ui: Checkbox docs (#23141)

* Add "When to use" info to Checkbox.mdx

Added info about how checkboxes generally work and when to use another component instead.

* Replaced words with proper component names

* Update Checkbox.mdx

Elaborate on explanations. Add examples for how to use checkboxes the user-friendliest way.

* Apply suggestions from code review

Co-authored-by: Dominik Prokop <dominik.prokop@grafana.com>

Co-authored-by: Tobias Skarhed <tobias.skarhed@gmail.com>
Co-authored-by: Tobias Skarhed <1438972+tskarhed@users.noreply.github.com>
Co-authored-by: Dominik Prokop <dominik.prokop@grafana.com>

packages/grafana-ui/src/components/Forms/Checkbox.mdx

@@ -5,6 +5,27 @@ import { Checkbox } from "./Checkbox";
 
 # Checkbox
 
+### When to use
+
+Checked represents true, un-checked represent false. So you can use them to select a binary option or multiple options in a set. `Checkbox` can be used in groups, where the single checkboxes have no dependencies. That means that selecting one doesn’t affect any other `Checkbox`. When adding a description to your `Checkbox`, write positive statements so that "checked" means "yes" and not "no". That way, you can avoid confusion.
+
+**DO:** [ ] Hide options
+**DON'T:** [ ] Do not show options
+
+Checkboxes typically only trigger changes after sending a form. If your component should trigger a change immediately, it's better to use a toggle switch instead. Furthermore, checkboxes are not mutually exclusive. That means that selecting one will not disable the others or impact them in any other way. If you want to offer a mutually exclusive choice, use `RadioButtonGroup` or a `Select` dropdown.
+
+**DO:**
+Show series
+[ ] A-series
+[ ] B-series
+[ ] C-series
+
+**DON'T:**
+Show only
+[ ] A-series
+[ ] B-series
+[ ] C-series
+
 ### Usage
 
 ```jsx