Small update to Type checks and casts page

[sarahhaggarty]

This PR updates the Type checks and casts page to make it clear earlier in the page that generics documentation is available on another page. Other changes have been added, like an introduction and other modifications, to tidy up the page a bit.

This PR resolves KT-57270.

[danil-pavlov]

Nice update! I'm just wondering why you opted for an xml table instead of Markdown? We usually try to use md syntax because it's more readable except for special cases when it's not enough
Is it because of the necessary table header in md tables? You can still add something like Element | Condition at the top of the table

[sarahhaggarty]

Nice update! I'm just wondering why you opted for an xml table instead of Markdown? We usually try to use md syntax because it's more readable except for special cases when it's not enough Is it because of the necessary table header in md tables? You can still add something like Element | Condition at the top of the table

Thanks @danil-pavlov ! Yes, it's because I wanted to use a table without a header, which is only possible via XML right now. Originally this was just a bulleted list but I think it is easier to read in a table format. I couldn't find header names that I liked unfortunately. Even "element" doesn't seem relevant enough to me for the first column 🤔 Is it OK to stick with the XML or could you help me find better header names?

[danil-pavlov]

I like the table idea and I can't come up with anything better than "Variables and properties", so let's keep the XML table as is