Typehints for getHeaderMargin() and setHeaderMargin() are inconsistent

[fisharebest]

This PR just updates a couple of inconsistent type-hints in the phpdoc.

The header/footer margins are both float, but the getters/setters have inconsistent PHPDOC.

getFooterMargin() has @return float, but setFooterMargin() has @param int $fm.

getHeaderMargin() has @return float, but setHeaderMargin() has @param int $hm.

[codecov-commenter]

Codecov Report

Merging #598 (7d76401) into main (2fb1c01) will not change coverage. The diff coverage is n/a.

:mega: This organization is not using Codecov’s GitHub App Integration. We recommend you install it so Codecov can continue to function properly for your repositories. Learn more

@@           Coverage Diff           @@
##             main     #598   +/-   ##
=======================================
  Coverage   69.33%   69.33%           
=======================================
  Files         128      128           
  Lines       27022    27022           
=======================================
  Hits        18735    18735           
  Misses       8287     8287           

Flag	Coverage Δ
php-5.3-ubuntu-latest	68.85% <ø> (+<0.01%)	:arrow_up:
php-5.4-ubuntu-latest	68.85% <ø> (-0.01%)	:arrow_down:
php-5.5-ubuntu-latest	68.85% <ø> (+<0.01%)	:arrow_up:
php-5.6-ubuntu-latest	68.91% <ø> (ø)
php-7.0-ubuntu-latest	71.59% <ø> (ø)
php-7.1-ubuntu-latest	73.07% <ø> (ø)
php-7.2-ubuntu-latest	72.94% <ø> (-0.01%)	:arrow_down:
php-7.3-ubuntu-latest	72.94% <ø> (ø)
php-7.4-ubuntu-latest	72.93% <ø> (-0.01%)	:arrow_down:
php-8.0-ubuntu-latest	72.94% <ø> (-0.01%)	:arrow_down:
php-8.1-ubuntu-latest	72.94% <ø> (-0.01%)	:arrow_down:
php-8.2-ubuntu-latest	72.94% <ø> (-0.01%)	:arrow_down:
php-nightly-ubuntu-latest	72.94% <ø> (+<0.01%)	:arrow_up:

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
tcpdf.php	67.90% <ø> (ø)

... and 1 file with indirect coverage changes

Help us with your feedback. Take ten seconds to tell us how you rate us. Have a feature suggestion? Share it here.

[fisharebest]

that's okay, but could you also add @var float on the properties?

Sure!

I wasn't sure of the project's policy - so I just changed the external interfaces.