While here pad line numbers with spaces instead of zeroes to match the blob view.

positive feedback from Kyle Ackerman ok/tweak tracey@

ok tracey@

Diff from Kyle Ackerman. tracey@ and I likes it.

while here clean up some *_header id not used / not needed.

there's no need to override the background-color for the 'even' row. This will simplify the addition of a dark mode.

ok tracey@

The repo_write process still announces HEAD twice, once with its symref target and once with the resolved symref object hash. I cannot recall if this is deliberate but let's accept it for now to avoid test failures being flagged due to this issue, which is mostly cosmetic.

This should prevent a use-after-free crash I observed in gotwebd. ok op@