Simply remove trailing whitespace.

Impose a little consistency in the <description> field, as discussed briefly on docs@httpd.a.o

Syntax updates for mod_h*.xml, mod_i*.xml

Similiar? Never hoid of such.

Changes to mod_heart* docs upon review by rjung

Update heartbeat module documentation, add documentation for mod_watchdog

fill in the heartbeat modules' documentation.

Cleanup effort in prep for GA push: Trim trailing whitespace... no func change

Add incomplete documents for mod_heartbeat and mod_heartmonitor.