Add additional format options for os/clock

[wishdev]

Allows for more flexibility in the returned value from os/clock

[sogaiu]

Some minor things about the proposed docstring:

For this bit of text in the docstring:

{seconds, nanoseconds}

May be it's better to not use curly braces as that's what's used for the literal syntax of structs.

Perhaps square brackets would work better?

Also, slight typo here?

• :int: Return the number of seconds as am integer

May be "an" is what was intended (not "am"), though may be there is some humor value...

[wishdev]

Fixed, thanks for the review!

[sogaiu]

Nice to have the tests :)

I tried the branch here manually successfully and the tests passed too.