Detect malformed closing tags as errors in ApacheConfLexer

[catatonicprime]

Discovered this issue while fuzzing a parser I've been working on. When a scoped directive's closing tag is malformed with whitespace/newlines prior to the '>' this will generate an error during httpd's config test.

e.g.

<VirtualHost "test"
</VirtualHost
>

or

<VirtualHost "test"
</VirtualHost >

Will cause this error:

httpd: Syntax error on line 2 of /usr/local/apache2/conf/httpd.conf: </VirtualHost> directive missing closing '>'

This patch aligns the token stream to more accurately detect this error. I identify open tags vs. closing tags by the absence or presence of the '/' after the '<', respectively. The opening tags should maintain all previous functionality. The closing tags will now be restricted to non-whitespace characters within.

I've included a positive test and negative test related to this specific issue. The negative test (test_malformed_scoped_directive_closing_tag) token stream was derived after the patches. The positive test (test_normal_scoped_directive) is present to ensure expected functionality is maintained.

[Anteru]

Merged, thanks!