changelog.md: Group the new `to` procs (#15522)
changelog.md: Group the new `to` procs (#15522)

* changelog.md: Group the new `to` procs [ci skip]

This also moves the `critbits.toCritBitTree` entry from the "Language
Changes" section to the "Standard library additions and changes"
section.

* changelog.md: Remove extra space
dom96/Nim,dom96/Nim,dom96/Nim,dom96/Nim,dom96/Nim,dom96/Nim,dom96/Nim