syntax-check: Don't check non-reentrant functions in docs

Otherwise constructions like "random (used by default)" end up breaking
syntax check by apparently using non-reentrant functions.

cfg.mk

@@ -813,7 +813,7 @@ exclude_file_name_regexp--sc_prohibit_newline_at_end_of_diagnostic = \
   ^src/rpc/gendispatch\.pl$$
 
 exclude_file_name_regexp--sc_prohibit_nonreentrant = \
-  ^((po|tests)/|docs/.*py|run.in$$)
+  ^((po|tests)/|docs/.*(py|html\.in)|run.in$$)
 
 exclude_file_name_regexp--sc_prohibit_raw_allocation = \
   ^(src/util/viralloc\.[ch]|examples/.*|tests/securityselinuxhelper.c)$$