DEP: Unify naming in constants

The following names in constants.py do not match the usual scheme and should be migrated to their proper names with a deprecation process:

• FileSpecificationDictionaryEntries.(Type|Mac|Unix|Cl)
• TypArguments (why not TypeArguments or an alignment-related name?)
• TypFitArguments (why not FitTypes or similar?)
• AnnotationDictionaryAttributes.(Type|Subtype|Rect|Contents|Border|StructParent)
• InteractiveFormDictEntries.(Fields|NeedAppearances|SigFlags)
• FieldDictionaryAttributes.(Parent|Kids|Ff|Opt)
• FieldDictionaryAttributes.FfBits (all values should be constant names)
• CheckboxRadioButtonAttributes.Opt
• OutlineFontFlag (all values should be constant names)

Please note that this list might be incomplete.

Before migrating them, we should ensure to check whether renaming them to the usual pattern for constants might cause conflicts due to possible duplicate names (see GraphicsStateParameters with OP vs. op for example). If there can be a conflict, these ideally should be documented properly.