Found typo in table_block.md

[kojoidrissa]

I found a typo in the 5.2.x version of this document

[squash-labs]

Manage this branch in Squash

Test this branch here: https://kojoidrissapatch-1-wef9p.squash.io

[gasman]

Thanks @kojoidrissa! We only update older versions of the docs when a patch release comes out, and there are no current plans for another 5.2.x release - but I've merged this now, so that the correction will be in place if another release happens in future.