This commit modifies the Place as follow:
* remove 'ty' from ProjectionKind
* add type information into to Projection
* replace 'ty' in Place with 'base_ty'
* introduce 'ty()' in `Place` to return the final type of the `Place`
* introduce `ty_before_projection()` in `Place` to return the type of
  a `Place` before i'th projection is applied

Closes rust-lang/project-rfc-2229#5

Shrink ParamEnv to 16 bytes

r? @nnethercote

x.py check passes but I haven't tried running perf or tests

typeck: adding type information to projection

This commit modifies the Place as follow:
* remove 'ty' from ProjectionKind
* add type information into to Projection
* replace 'ty' in Place with 'base_ty'
* introduce 'ty()' in `Place` to return the final type of the `Place`
* introduce `ty_before_projection()` in `Place` to return the type of
  a `Place` before i'th projection is applied

Closes rust-lang/project-rfc-2229#5

Rollup of 14 pull requests

Successful merges:

 - #70563 ([rustdoc] Page hash handling)
 - #73856 (Edit librustc_lexer top-level docs)
 - #73870 (typeck: adding type information to projection)
 - #73953 (Audit hidden/short code suggestions)
 - #73962 (libstd/net/tcp.rs: #![deny(unsafe_op_in_unsafe_fn)])
 - #73969 (mir: mark mir construction temporaries as internal)
 - #73974 (Move A|Rc::as_ptr from feature(weak_into_raw) to feature(rc_as_ptr))
 - #74067 (rustdoc: Restore underline text decoration on hover for FQN in header)
 - #74074 (Fix the return type of Windows' `OpenOptionsExt::security_qos_flags`.)
 - #74078 (Always resolve type@primitive as a primitive, not a module)
 - #74089 (Add rust-analyzer to the build manifest)
 - #74090 (Remove unused RUSTC_DEBUG_ASSERTIONS)
 - #74102 (Fix const prop ICE)
 - #74112 (Expand abbreviation in core::ffi description)

Failed merges:

r? @ghost