Mostly apply jshint structure to related-posts

Remaining issues:

   modules/related-posts/related-posts.js
     83 |                if ( '' == post.img.src ) {
                                   ^ Expected '===' and instead saw
'=='.
     90 |                if ( '' != post.img.src ) {
                                   ^ Expected '!==' and instead saw
'!='.
    106 |            if ( '' == anchor.search ) {
                               ^ Expected '===' and instead saw '=='.