Update typecasting.md

[soerenwolfers]

Solves duckdb/duckdb#13847 (sadly).

From what I can tell, BOOL -> INTEGERTYPES is the only example of this special type of casting?

Maybe one should get one final confirmation whether it's worth documenting this special type of cast rather than simply dropping it and gaining more PostgreSQL compatibility for it (just to reiterate: I'm all for implicit casts to programatically selected parent types, I just question the value of allowing more implicit casts in this situation than in other implicit cast situations.)

By the way: do you have the HTML for the typecasting matrix? I'd like to resolve #2791 too by adding INTEGER_LITERAL / STRING_LITERAL / NUMERIC_LITERAL to the table (at which point I'd also add the "combination cast" from bool to int to the table)

[szarnyasg]

IIRC the typecasting matrix was a Google Sheets sheet. I wanted to re-do it in Markdown as three column table (from, to, what type of cast is allowed) but did not get to this so far. Would you be interested in picking this up?

[soerenwolfers]

Yeah, can do. Long-format is more in the spirit of SQL too.

[soerenwolfers]

Although... are you sure you want a table with 576 entries in the docs? Maybe should that table only include positive entries? That'd be around 100.