unposted: NEWS: document new zparseopts features
54362: zparseopts: support empty optspec
54361 (tweaked): zparseopts: print friendlier usage errors, add -n option
54329 + 54339: docs: replace pdfroff by `groff -Tpdf`
54318: mathfunc: add isnan() and isinf(). also document NaN + Inf
54313: convfloat: use consistent capitalisation for NaN, Inf, and -Inf
replace roff2* by equivalent groff commands
github #156: _git: fix --git-dir and --work-tree options when used with parameters