core: Clean up comments for low-res clocks
core: Clean up comments for low-res clocks

Formatting, grammar, spelling, line length.

dreamsxin/seastar,scylladb/seastar,dreamsxin/seastar,dreamsxin/seastar,scylladb/seastar,syuu1228/seastar,cloudius-systems/seastar,avikivity/seastar,avikivity/seastar,avikivity/seastar,cloudius-systems/seastar,cloudius-systems/seastar,syuu1228/seastar,scylladb/seastar,syuu1228/seastar