deftype and defmethod syntax major changes (#3094)

Major change to how `deftype` shows up in our code:
- the decompiler will no longer emit the `offset-assert`,
`method-count-assert`, `size-assert` and `flag-assert` parameters. There
are extremely few cases where having this in the decompiled code is
helpful, as the types there come from `all-types` which already has
those parameters. This also doesn't break type consistency because:
  - the asserts aren't compared.
- the first step of the test uses `all-types`, which has the asserts,
which will throw an error if they're bad.
- the decompiler won't emit the `heap-base` parameter unless necessary
now.
- the decompiler will try its hardest to turn a fixed-offset field into
an `overlay-at` field. It falls back to the old offset if all else
fails.
- `overlay-at` now supports field "dereferencing" to specify the offset
that's within a field that's a structure, e.g.:
```lisp
(deftype foobar (structure)
  ((vec    vector  :inline)
   (flags  int32   :overlay-at (-> vec w))
   )
  )
```
in this structure, the offset of `flags` will be 12 because that is the
final offset of `vec`'s `w` field within this structure.
- **removed ID from all method declarations.** IDs are only ever
automatically assigned now. Fixes #3068.
- added an `:overlay` parameter to method declarations, in order to
declare a new method that goes on top of a previously-defined method.
Syntax is `:overlay <method-name>`. Please do not ever use this.
- added `state-methods` list parameter. This lets you quickly specify a
list of states to be put in the method table. Same syntax as the
`states` list parameter. The decompiler will try to put as many states
in this as it can without messing with the method ID order.

Also changes `defmethod` to make the first type definition (before the
arguments) optional. The type can now be inferred from the first
argument. Fixes #3093.

---------

Co-authored-by: Hat Kid <6624576+Hat-Kid@users.noreply.github.com>

test/decompiler/reference/jak2/engine/load/decomp_REF.gc

@@ -40,16 +40,13 @@
 
 ;; definition of type huf-dictionary-node
 (deftype huf-dictionary-node (structure)
-  ((zero uint16  :offset-assert   0)
-   (one  uint16  :offset-assert   2)
+  ((zero  uint16)
+   (one   uint16)
    )
-  :method-count-assert 9
-  :size-assert         #x4
-  :flag-assert         #x900000004
   )
 
 ;; definition for method 3 of type huf-dictionary-node
-(defmethod inspect huf-dictionary-node ((this huf-dictionary-node))
+(defmethod inspect ((this huf-dictionary-node))
   (when (not this)
     (set! this this)
     (goto cfg-4)
@@ -259,7 +256,7 @@
 
 ;; definition for method 16 of type level
 ;; INFO: Used lq/sq
-(defmethod update-vis! level ((this level) (vis-info level-vis-info) (unused uint) (in-bsp-vis-string (pointer uint8)))
+(defmethod update-vis! ((this level) (vis-info level-vis-info) (unused uint) (in-bsp-vis-string (pointer uint8)))
   (local-vars (t0-3 uint128) (extra-vis-length int) (extra-vis-dest (pointer int8)))
   (let* ((cam-leaf-idx (-> vis-info from-bsp current-leaf-idx))
          (curr-vis-string-offset (-> vis-info current-vis-string))