[Outreachy] Microproject: use Q_() in builtin/checkout.c

Hi Usman, Christian and Siddharth,

Thank you Usman for the welcome. I took some time to look into the microproject I want to work on and one that got my interest is the Q_() pluralization microproject. I will like to work on builtin/checkout.c. I searched the list archive and I didn't see anyone working on this file yet.

I noticed two places that can get improved with Q_():

Line 1088, " ... and %d more.\n": this is at the end of the warning Git shows when someone leaves a detached HEAD and so commits might be left behind. Git lists up to four commits and then shows this line for the rest.

Line 1492, "only one reference expected, %d given.": this appears when more than one reference is given before --, e.g. git checkout a b --. In both cases the number is always 2 or more, so in English the plural is always shown. But for languages like Polish, which have different plural forms for 2-4 and for 5 and above, it will be inconsistent to use the same form for all cases.

In po/pl.po, the first message currently has only one translation slot. So using Q_() can let have proper translation.

I noticed that line 1405 in builtin/checkout.c has the same issue. The same message also appears in builtin/worktree.c at lines 812 and 951.

So I have two questions:

1. Is it OK to convert these messages to Q_(), even though English
will always show the plural?
2. Should I also include line 1405 in the patch, which will mean
changing the same message in builtin/worktree.c
as well, or should I keep the patch just limited to the first two
messages for now

Regards, Mudi