Fix some formatting in linter README
Fix some formatting in linter README

One of the tables had an extra row, and one of the code examples did not
have any syntax highlighting. Fix both.

Change-Id: Ie653491af926de58d88edd31511f4c48d51444ba
Reviewed-on: http://gerrit.causes.com/36700
Tested-by: jenkins <d95b56ce41a2e1ac4cecdd398defd7414407cc08@causes.com>
Reviewed-by: Shane da Silva <6f6e68d1df92f30cb4b3ce35260ddf94a402f33d@causes.com>

gajus/scss-lint,ivantsepp/scss-lint,baileyparker/scss-lint,davecarter/scss-lint,golmansax/scss-lint,cih/scss-lint,ingdir/scss-lint,leseulsteve/scss-lint,dwayhs/scss-lint,teoljungberg/scss-lint,chatzipan/scss-lint,philipgiuliani/scss-lint,gatero/scss-lint,bkeepers/scss-lint