Reduced number of allocated limbs after calling mpz_remove

[Albin Ahlbäck]

Hello,

Standing at the following commit:

changeset:   18465:7ecb3b2beea1
tag:         tip
user:        Niels Möller <nisse at lysator.liu.se>
date:        Sun Feb 18 20:20:57 2024 +0100
summary:     mini-gmp: Fix bug in gcdext canonicalization, and 
strengthen related tests.

I have noticed that `mpz_remove` may reduce the number of allocated 
limbs after a call.

I haven't looked into this too much, but I suppose it is due to the 
variable `x` being initialized in the routine, whose limbs I believe are 
allocated in `mpz_tdiv_q`, is then being swapped with `dest`.

It is stated in the documentation that "mpz_t and mpq_t variables never 
reduce their allocated space.", which is sort of true given that `x` and 
`dest` are only being swapped, but that requires the user to know what 
the internals are doing.

Is this the expected behavior? Have I overlooked something perhaps? 
Please let me know if you need more information.

Best,
Albin