document `isSafeImmediate` and `parseSafeImmediateValue` behavior in `eb.case()`.

[igalklebanov]

Hey 👋

Value-first methods, in most cases, append to parameters - unless you use eb.lit or sql.lit.

For some undocumented reason, eb.case()'s then and else values are injected into the query string for numbers, booleans and nulls - possibly because eb.lit('string') is not allowed.

This is surprise behavior!

Investigate why that was chosen as a strategy.
Remove isSafeImmediateValue and parseSafeImmediateValue if there's no good reason.

We need to document this.

[koskimas]

That was chosen so that the database type can be inferred by the DB engine. Otherwise everything is text. Try to select a case expression where one then is a number or boolean. It gets returned as a string.

Another option would be to use casts, but how to do that in a database agnostic way?

[igalklebanov]

Thanks! Turning this one into a documentation issue for now.