Update "how to call an event handler" article to be more general

[Youssef1313]

I also strongly recommend re-writing the sample to be more generic. it's currently tied to WinForms while it's supposed to explain a more general thing "Events".

Originally posted by @Youssef1313 in https://github.com/dotnet/docs/pull/20130

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Document Details

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• ID: 768a4cc5-d734-2ee4-f853-5cc5e510f06d
• Version Independent ID: 891620e5-6d3f-d730-a69e-c0206cae1020
• Content: How to: Call an Event Handler - Visual Basic
• Content Source: docs/visual-basic/programming-guide/language-features/procedures/how-to-call-an-event-handler.md
• Product: dotnet-visualbasic
• GitHub Login: @KathleenDollard
• Microsoft Alias: kdollard

[Youssef1313]

I forgot to add Document Details section from the beginning. This needs rerun-labels label so the bot can apply the correct label(s).

[BillWagner]

/cc @KathleenDollard

I like this idea @Youssef1313

Would you like to take this one on?

[Youssef1313]

I currently have no great ideas. But I'll certainly work on it if I got something in mind.

[zspitz]

I would suggest using an example with Timer.Elapsed as it is the quintessential event.