Fix HamlCommentNode#text
Fix HamlCommentNode#text

There were a couple more bugs with this implementation when extracting
text from comments at the end of a HAML document or containing spaces.

Change-Id: Ie525c10403da4d3048a54d605a5cd630e52b3bfc
Reviewed-on: http://gerrit.causes.com/44995
Tested-by: jenkins <d95b56ce41a2e1ac4cecdd398defd7414407cc08@brigade.com>
Reviewed-by: Shane da Silva <67fb7bfe39f841b16a1f86d3928acc568d12c716@brigade.com>

skateman/haml-lint,mzp/haml-lint