Chalk may incorrectly format a table's header and first row

## Description

At some window and font size combinations, the formatting may be broken:

- at the end of a table header
- at the beginning and end of a table's first row

For example, from `chalk dump --help`:


And from `chalk insert --help`:


## Impact

Chalk table output may sometimes be harder to read.

~But it looks like this may be the same underlying issue that has blocked us from updating the docs on the marketing-site: https://github.com/crashappsec/marketing-site/pull/192~

Edit: that PR was created before this exact problem was introduced.

## Steps to Reproduce

Using the latest release (chalk v0.3.1), run a `help` command and scroll down. At some window size and font combinations, the table is formatted incorrectly.

I cannot reproduce this issue with the previous release, chalk v0.3.0. The commit that introduced the issue is https://github.com/crashappsec/chalk/commit/c238960a287f457e589f09e2f3b9df7db8584832.

## Other information

Maybe related: #143

Start by reproducing the table rendering problem with the chalk help commands at different window sizes and font combinations. Compare the current release with v0.3.0, inspect commit c238960a, and review related issue #143; done means the header and first row render correctly across the reported combinations.

Written by the indexing model from the issue text.