Added zero-padding to timestamp output

[rhillefeld]

Fixes #31272
Fixed the output of nowString() to properly zero-pad individual timestamp components (hours, minutes, seconds, milliseconds). This affects the log output of tsserver.

[sandersn]

The code looks fine to me, but @sheetalkamat @amcasey or @uniqueiniquity will know what the ramifications of changing the format are.

[amcasey]

Love the concept, but please extract a function. Consider mimicking/unifying with padLeft.

[ghost]

All CLA requirements met.

[rhillefeld]

Thank you for your feedback. I didn't realize those functions existed already and I'm a fan of unifying similar capabilities where it makes sense. With this update, we can pad using any string, similar to padStart() and padEnd() in JS.

Even though the original bug didn't need it, I also updated padRight() for consistency. Most of the code is obviously the same as padLeft() but I thought refactoring out just those few lines in common was overkill for this case.

I'd like to test this further but wanted your feedback on this change before I spend too much time doing that...

[amcasey]

Thanks for the update! One more suggestion, but looks good.

[amcasey]

Nice! Thanks for the changes.

[amcasey]

@rhillefeld Happy to merge if you're done.

[rhillefeld]

@amcasey yes, that should do it. Thanks!