[SSSD] [sssd PR#965][comment] certmap: mention special regex characters in man page

[mzidek-rh]

  URL: https://github.com/SSSD/sssd/pull/965
Title: #965: certmap: mention special regex characters in man page

mzidek-rh commented:
"""
ACK.
"""

See the full comment at https://github.com/SSSD/sssd/pull/965#issuecomment-565598155