What a "word" is when talking about sizes is confusing because it's a
highly overloaded term. Intel, Microsoft, and GDB are just a few vendors
that have their own definition of what a "word" is. Specs that used the
"wordsize" guard actually were mostly testing for the size of the C
`long` fundamental type, so rename the guard for clarity.

Also, get the size of `long` directly from RbConfig instead of guessing
using Integer#size. Integer#size is not guaranteed to have anything to
do with the `long` type.

[Feature #19236]

In Ruby 3.3, `Hash.new` shall print a deprecation warning if keyword arguments
are passed instead of treating them as an implicit positional Hash.

This will allow to safely introduce a `capacity` keyword argument in 3.4

Co-authored-by: Jean Boussier <byroot@ruby-lang.org>

When `freeze: true` argument is passed.

[Bug #19427]