docs: Fix grammar and consistency in loader doc

LoaderAndLayerInterface.md:
- entry-point => entry point
- MacOS => macOS (except in API function names)
- on the applications surfaces => on the application's surfaces
- Because layers are optionally, => Because layers are optional,
- a child of a one of the above => a child of one of the above
- action / operation => action or operation
- fixed indentation of the dispatch table description to what I think was intended
- the application and/or system can specify => the application and the system can each specify
- linking to the .dll and .so versions of the loader => linking to the dynamic versions of the loader
  (because .dylib is also a dynamic link)
- platform specific => platform-specific
- dlsym() => `dlsym` (to match usage elsewhere)
- setup => set up (when used as a verb)
- don't break link references across lines
  e.g. [XX XX XX XX](YY) should never be broken in the YY clause
- 3 enabled layers => three enabled layers (spell numbers up to 10)
- backwards compatibility => backward compatibility
- Windows paths use "\" instead of "/"
- libXXX.YYY => `libXXX.YYY` (to match usage elsewhere)
- Layers => layers (to match usage elsewhere, where "Layers" isn't a capitalized term)
- bottommost => bottom-most (for consistency elsewhere)
- the VK_LAYER_XXX ... => the VK_LAYER_XXX layer (for consistency elsewhere)
- either end all list or table items with periods, or none of them
- Khronos approved => Khronos-approved
- hand-shake => handshake
- logical device (This depends => logical device (this depends
- other-hand => other hand
- filtering out of => filtering of
- JSON formatted => JSON-formatted
- /path/to/something => `/path/to/something` (to match usage elsewhere)
- system wide registries => system registries
- fixed some "*" entries (which generally must be escaed, "\*", in markdown)
- environment variable enabled layer => environment-variable-enabled layer
- The implementation of each intercept functions is => The implementation fo each intercept function is
- corrected some "it's" to "its", and vice versa
- the extension suffix of the file ends with ".json" => the extension suffix of the file is ".json"
- added commas to fix illegal JSON file content
- semi-colon separated => semi-colon-separated
- other minor grammar and consistency fixes