11194 syseventadm.1m: ERROR: using macro argument outside macro
This is required for mandoc 1.14.5 update (#11190) and "11195 Lint old man pages for errors with mandoc".

Before:
$ mandoc -Tlint -Werror ~/ws/illumos-gate/usr/src/man/man1m/syseventadm.1m 
mandoc: /export/home/newman/ws/illumos-gate/usr/src/man/man1m/syseventadm.1m:289:22: ERROR: using macro argument outside macro: \$A
mandoc: /export/home/newman/ws/illumos-gate/usr/src/man/man1m/syseventadm.1m:309:25: ERROR: using macro argument outside macro: \$A
mandoc: /export/home/newman/ws/illumos-gate/usr/src/man/man1m/syseventadm.1m:310:58: ERROR: using macro argument outside macro: \${
mandoc: /export/home/newman/ws/illumos-gate/usr/src/man/man1m/syseventadm.1m:310:45: ERROR: using macro argument outside macro: \${
mandoc: /export/home/newman/ws/illumos-gate/usr/src/man/man1m/syseventadm.1m:310:35: ERROR: using macro argument outside macro: \${


The -R $ALTROOT portion is not displayed correctly with updated mandoc.
After:
$ mandoc -Tlint -Werror /usr/share/man/man1m/syseventadm.1m 

$ mandoc -l /usr/share/man/man1m/syseventadm.1m 
...
         # syseventadm add -R $ALTROOT -v MYCO -c EC_ENV -s ESC_ENV_TEMP \
              /opt/MYCOenv/bin/ec_env_temp ${class} ${subclass} ${pathname}
...
         # syseventadm remove -R $ALTROOT -v MYCO -c EC_ENV -s ESC_ENV_TEMP \
              /opt/MYCOenv/bin/ec_env_temp ${class} ${subclass} ${pathname}
...
         # syseventadm list -v MYCO -c EC_ENV -s ESC_ENV_TEMP \
              vendor=MYCO class=EC_ENV subclass=ESC_ENV_TEMP \
              /opt/MYCOenv/bin/ec_env_temp ${class} ${subclass} ${pathname}
...