A single number shouldn't be interpreted as a year

[cakebaker]

uutils date interprets a single number as a year whereas GNU date interprets it as a time (without seconds). Some examples:

$ LC_ALL=C date -d "0"
Mon Aug  4 00:00:00 CEST 2025
$ LC_ALL=C date -d "23"
Mon Aug  4 23:00:00 CEST 2025
$ LC_ALL=C date -d "24"
date: invalid date '24'
$ LC_ALL=C date -d "159"
Mon Aug  4 01:59:00 CEST 2025
$ LC_ALL=C date -d "160"
date: invalid date '160'
$ LC_ALL=C date -d "2359"
Mon Aug  4 23:59:00 CEST 2025
$ LC_ALL=C date -d "2400"
date: invalid date '2400'
$ LC_ALL=C date -d "235910"
date: invalid date '235910'

$ cargo run -q date -d "0"
Fri Dec 31 22:34:08 LMT -0001
$ cargo run -q date -d "23"
Sat Dec 31 23:00:00 CET 2022
$ cargo run -q date -d "24"
Sun Dec 31 23:00:00 CET 2023
$ cargo run -q date -d "159"
Sun Dec 31 22:34:08 LMT 0158
$ cargo run -q date -d "160"
Mon Dec 31 22:34:08 LMT 0159
$ cargo run -q date -d "2359"
Wed Dec 31 23:00:00 CET 2358
$ cargo run -q date -d "2400"
Fri Dec 31 23:00:00 CET 2399
$ cargo run -q date -d "235910"
date: invalid date '235910'