[0037] Describe the `CheckAccessFullyMapped` and Status Overload

[inbelic]

The Texture and Sampler Types currently does not provide a description for CheckAccessFullyMapped or how we can handle the status overload parameter.

The proposal must be updated to describe:

• Status parameter overloads for Load, Sample*, and Gather* methods that
  return a uint status value
• CheckAccessFullyMapped(uint status) intrinsic that returns bool
• How the status value is threaded through from the DXIL/SPIR-V texture
  operations

AC:

• Proposal updated with status parameter overloads for Load, Sample*,
  and Gather*
• Proposal updated with CheckAccessFullyMapped intrinsic description
• DXIL/SPIR-V translation details included
• Create issues for the new work described