ArrayMesh.add_surface_from_arrays(...) missing param doc, add_blend_shape(...)

**Your Godot version:**
3.2.3
**Issue description:**

ArrayMesh:
- add_surface_from_arrays ( PrimitiveType primitive, Array arrays, Array blend_shapes=[ ], int compress_flags=97280 )
is documenting only two first parameters
- compress_flags can be found in ArrayFormat, not as [partially documented for ArrayMesh enumerations](https://docs.godotengine.org/en/stable/classes/class_arraymesh.html#enumerations), but in its [Mesh parent enumeration doc](https://docs.godotengine.org/en/stable/classes/class_mesh.html#enumerations)
- blend_shapes... arrays of what? how is passed the absolute/relative type of blend_shapes

- void add_blend_shape ( String name )
seems obscure without more context or example

**URL to the documentation page:**
https://docs.godotengine.org/en/stable/classes/class_arraymesh.html#class-arraymesh-method-add-surface-from-arrays