Fix some examples

H,
I'm new to Nim and GTK, I'm also a big fan of working through examples to learn new programming languages. I think it's a great way to get a feel for the syntax and semantics of a language.
I'm writing to request a fix for some examples . BTW I'm a big fan of your work on this library, and I think it's a great resource for Nim gui developers.

I've noticed a few errors in the examples :
**1-** [examples/widgets/adw/entry_row.nim](https://github.com/can-lehmann/owlkettle/blob/main/examples/widgets/adw/entry_row.nim), 


> Error: undeclared identifier: 'EntryRow'
candidates (edit distance, scope distance); see '--spellSuggest': 
 (3, 9): 'Entry'
 (3, 9): 'EntryError'

**2-** [examples/widgets/adw/switch_row.nim](https://github.com/can-lehmann/owlkettle/blob/main/examples/widgets/adw/switch_row.nim)

> Error: undeclared identifier: 'SwitchRow'
candidates (edit distance, scope distance); see '--spellSuggest': 
 (3, 9): 'Switch'

Thank you for your time and consideration.

