Cleanup: add note from T85517 fix

Cleanup: pass sizeof array element to PyC_AsArray

Replace the is_double argument which was only used for single/double
precision floats.

This allows supporting different sized int types more easily.

PyAPI: support different int sizes for PyC_AsArray

Fix memory leak with Python RNA property get callback errors

Failure to return a list of the expected size & type wasn't
decrementing the value, leaking a reference.

Caused by 127b5423d6203d521acb2b96b7de5534e8dbe79a a workaround for the
real error that was fixed f5e020a7a6ad6451fcaf075ae14f7014b8a4faea.

Cleanup: reduce indentation in bpy.props

Remove unnecessary NULL checks.

Cleanup: spelling

PyAPI: add multi-dimensional array conversion utility functions

Add array conversion functions that take dimension arguments.

- PyC_AsArray_Multi (version of PyC_AsArray).
- PyC_Tuple_PackArray_Multi_* (version of PyC_Tuple_Pack_*).

PyAPI: support multi-dimensional arrays for bpy.props vector types

- Multi-dimensional boolean, int and float vector types are supported.
- A sequence of int's for the "size" is used to declare dimensions.
- Nested sequences are required for default arguments.

Now it's possible to define matrix properties, for e.g:

bpy.props.FloatVectorProperty(size=(4, 4), subtype='MATRIX')

Cleanup: use PyC_AsArray_FAST function where possible

Oversight in 2453dc1b0ecad21a84b45e8c900a16cc42fa12f1.

Fix gpu.types.GPUTexture crash when the size argument was too big

Missing length check on the size argument before copying it
into a fixed size buffer.