Fix comment for DisallowSpaceIndentSniff

This should be referencing spaces are problematic, and not tabs.
Merge pull request #125 from sqmk/patch-1

Fix comment for DisallowSpaceIndentSniff
Fixed bug #19969 : Sniffs with namespace not recognized in reports
Merge branch 'master' of https://github.com/squizlabs/PHP_CodeSniffer