Docs: a more precise description of 5420-5428

Signed-off-by: John Thornton <jthornton@gnipsel.com>
build system: remove useless assert

The RTSRCS variable is never set and never read, so this assert makes no sense.
remap docs: The inifile var is PYTHON_APPEND

Signed-off-by: Jeff Epler <jepler@unpythonic.net>
Merge remote-tracking branch 'origin/2.6'

Signed-off-by: Jeff Epler <jepler@unpythonic.net>