Ensure endless rules are on a single line

[eric1234]

In 7df506e I had added an endless rule but I made a mistake in the semantic predicate. I examined the first token (aka 'rule') and not the last one (the "parsing expression").

@cjhealth fixed it up for me in 229d2c8 but it seems prudent to add a test to verify this.

This commit adds this test. If I update the test replacing the newline with just a normal space between the literals then test fails. But with the newline in the parsing expression the test passes (i.e. it fails to parse).