Hey 👋

closes #891.

This PR makes it so that the following is assignable to Expression<SqlBool>:

eb('age', sql`OP`, 1)

Where before it would inherit the type from the first argument, and fail when it was not assignable to SqlBool in common contexts.

This was also true when explicitly providing the custom operator a return type.

So now, as an experiment, we'll allow you to dictate the binary expression's return type:

expectAssignable<Expression<SqlBool>>(eb('age', sql<SqlBool>`OP`, 1)) 
expectAssignable<Expression<number>>(eb('age', sql<number>`OP`, 1))
expectAssignable<Expression<string>>(eb('age', sql<string>`OP`, 1))