* man/login.defs.d/SYS_UID_MAX.xml, man/login.defs.d/SYS_GID_MAX.xml:

* man/login.defs.d/SYS_UID_MAX.xml, man/login.defs.d/SYS_GID_MAX.xml:
  Document new variables.
* man/newusers.8.xml, man/login.defs.5.xml,
  man/login.defs.d/GID_MAX.xml, man/login.defs.d/UID_MAX.xml:
  newusers uses now the GID_MAX, GID_MIN, UID_MAX, UID_MIN,
  SYS_GID_MAX, SYS_GID_MIN, SYS_UID_MAX, and SYS_UID_MIN variables.
* man/groupadd.8.xml, man/login.defs.5.xml: groupadd uses now the
  SYS_GID_MAX, and SYS_GID_MIN variables.
* man/login.defs.5.xml: useradd uses now the SYS_GID_MAX,
  SYS_GID_MIN, SYS_UID_MAX, and SYS_UID_MIN variables.