Fixing issue #1223: pdf.font_style now behaves like pdf.set_font

[smilerightnow]

Fixes #1223

Checklist:

• The GitHub pipeline is OK (green),
  meaning that both pylint (static code analyzer) and black (code formatter) are happy with the changes of this PR.

• A unit test is covering the code added / modified by this PR

• This PR is ready to be merged

• [N/A] In case of a new feature, docstrings have been added, with also some documentation in the docs/ folder

• A mention of the change is present in CHANGELOG.md

By submitting this pull request, I confirm that my contribution is made under the terms of the GNU LGPL 3.0 license.

[andersonhc]

Hi @smilerightnow
Pylint is failing on the file below

Run pylint fpdf test tutorial/tuto*.py
************* Module fpdf.fpdf
fpdf/fpdf.py:1946:0: C0303: Trailing whitespace (trailing-whitespace)```

[smilerightnow]

thanks @andersonhc for pointing it out, I removed the 4 spaces :)