Change help text for `timetrace create record` to honor `use12hours`

[sudiptog81]

Fixes #190.

Using Use12Hours in core.Timetrace.Config() to use a different string for the usage help text for timetrace create record.

Behaviour

use12hours: false in config.yaml

Create a new record
  timetrace create record <PROJECT KEY> {<YYYY-MM-DD>|today|yesterday} <HH:MM> <HH:MM> [flags]

Flags:
  -b, --billable   mark tracked time as billable
  -h, --help       help for record

use12hours: true in config.yaml

Create a new record
  timetrace create record <PROJECT KEY> {<YYYY-MM-DD>|today|yesterday} <HH:MMPM> <HH:MMPM> [flags]

Flags:
  -b, --billable   mark tracked time as billable
  -h, --help       help for record