v/rpc: use std::constructible_from when appropriate

[tchaikov]

Cover letter

for better readability

Signed-off-by: Kefu Chai [email protected]

Release notes

• none

[tchaikov]

not sure if tiny changes like this are appropriate. if not, i'd be happy to close this one =)

[jcsp]

This looks fine to me (I hadn't heard of constructible_from before, still learning all the C++20 bits!)

[tchaikov]

same here! still crunching the ranges =)

[tchaikov]

@jcsp hi John, is this change pending on another reviewer or a round of internal test?

Just wanted to understand the process in general.