Add either AsRef/AsMut or Deref/DerefMut impls to InlineAny for getting &dyn Any/&mut dyn Any which references the value in the InlineAny

Creating a &dyn Any from value and vtable pointers is currently unstable behind ptr_metadata (rust-lang/rust#81513)

• Wait for ptr_metadata (or implement on nightly behind a feature?)
• AsRef, Deref, or both?
• Implement

Current documentation is very sparse, not very detailed

• Go into more depth in the descriptions
• Add examples

InlineAny drops its contained value by taking the drop_in_place of the provided type and transmuting it to unsafe fn(*mut ()) then calling that when dropped. Is this okay?

Specific questions

• Is this a valid function pointer?
  

  inline_any/src/lib.rs

  Line 34 in 8a55296

  let drop_in_place = unsafe { transmute(std::ptr::drop_in_place::<T> as unsafe fn(*mut T)) };

• Is this valid to call, assuming the data pointed to is a valid instance of T where T is the type self.drop_in_place expects?
  

  inline_any/src/lib.rs

  Line 100 in 8a55296

  unsafe { (self.drop_in_place)(self.data.as_mut_ptr::<()>()) }