PR: Provide icon size when creating an IconWidget

[StSav012]

I suggest adding a size keyword-only argument to the constructor of IconWidget to avoid extra setIconSize and update calls.

This way,

icon_widget: qta.IconWidget = qta.IconWidget('mdi.web', color='blue')
icon_widget.setIconSize(QtCore.QSize(32, 32))
icon_widget.update()

turns into

icon_widget: qta.IconWidget = qta.IconWidget('mdi.web', color='blue', size=QtCore.QSize(32, 32))

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And I fixed a couple of typos in the docstring of the class.

[dalthviz]

Thanks @StSav012 for your work here! Left a comment regarding some places and things that need an update to follow up with the change done at example.py and the usage there of the new size kwarg.

Other than that this LGTM 👍

Thanks again!

[dalthviz]

Thanks @StSav012 !