Fix calcTextSize to be used in a static context

[davfsa]

Description

calcTextSize was missing the static keyword. I also removed the final one because it seems inconsistent with the rest of methods

Type of change

• Minor changes or tweaks (quality of life stuff)
• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• This change requires a documentation update

[davfsa]

@SpaiR would it also be possible to create a release after this is merged?

Thanks!

[SpaiR]

@davfsa Thanks for the contribution!
I think it is possible to create release on the weekend.