Fix blob line number slightly enlarges on Android Chrome
When a file's line count exceeds certain amount (probably 130 or so?)
the line number rows slightly increases its vertical size and causes
misalign to a text line on its right.
This happens on Samsung Galaxy Tab S9 FE (Android 14), and does not
happen on Motorola Razr 40 Ultra (Android 15).
I still don't know which factor plays, but this patch fixes the bug.