Ability to set font height ratio

@hitfactory - can you provide more use cases for it? screenshots?
I've applied patch and set font ration to 4, if affected rendered PDF but has not affected /debug preview.
I'm not sure what's the use case for it.

@jannakha, thanks for following up.

Sorry, I don't have a screenshot but the use case is for making the line height of the font in the generated PDF match what you see in the browser since DomPDF applies a default line-height ratio of 1.1 as per https://github.com/dompdf/dompdf/blob/master/src/Options.php#L164.

You are right in recognising that it only modifies the PDF.

We were having an issue where the fonts in the generated PDF didn't look like what we were seeing in the browser.

@hitfactory thank you for your notes

can you please resolve merge conflicts?