lang/swi-pl: Add explicit readline dependency (D29353)
This unbreaks the build when using devel/samurai.
It previously got it through ninja->python->readline.
> Building package for swi-pl-8.2.3_1
pkg-static: Unable to access file /wrkdirs/usr/ports/lang/swi-pl/work/stage/usr/local/lib/swipl/doc/packages/readline.html:No such file or directory
pkg-static: Unable to access file /wrkdirs/usr/ports/lang/swi-pl/work/stage/usr/local/lib/swipl/lib/amd64-freebsd/readline4pl.so:No such file or directory
pkg-static: Unable to access file /wrkdirs/usr/ports/lang/swi-pl/work/stage/usr/local/lib/swipl/library/readline.pl:No such file or directory
- Error code 1
PR: 254678