migrate builtin functions to package

[k2tzumi]

T/O

[github-actions]

Code Metrics Report

	main (dd53be5)	#185 (06c55ec)	+/-
Coverage	78.1%	78.1%	+0.0%
Code to Test Ratio	1:0.8	1:0.8	+0.0

Details

  |                    | main (dd53be5) | #185 (06c55ec) |  +/-  |
  |--------------------|----------------|----------------|-------|
+ | Coverage           |          78.1% |          78.1% | +0.0% |
  |   Files            |             22 |             24 |    +2 |
  |   Lines            |           2707 |           2707 |     0 |
+ |   Covered          |           2114 |           2115 |    +1 |
+ | Code to Test Ratio |          1:0.8 |          1:0.8 |  +0.0 |
  |   Code             |           5222 |           5232 |   +10 |
+ |   Test             |           3970 |           4038 |   +68 |

Code coverage of files in pull request scope (71.1% → 71.4%)

Files	Coverage	+/-
builtin/compare.go	77.8%	+77.8%
builtin/time.go	100.0%	+100.0%
option.go	70.7%	-0.4%

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Reported by octocov

[k2tzumi]

I want to automatically expand the public functions of the buildin package.