Add field documentation for HashPatternNode

Author: herwinw

config.yml

@@ -2161,18 +2161,61 @@ nodes:
     fields:
       - name: constant
         type: node?
+        kind:
+          - ConstantPathNode
+          - ConstantReadNode
+        comment: |
+          Represents the optional constant preceding the Hash.
+
+              foo => Bar[a: 1, b: 2]
+                   ^^^
+
+              foo => Bar::Baz[a: 1, b: 2]
+                   ^^^^^^^^
       - name: elements
         type: node[]
         kind: AssocNode
+        comment: |
+          Represents the explicit named hash keys and values.
+
+              foo => { a: 1, b:, ** }
+                       ^^^^^^^^
       - name: rest
         type: node?
         kind:
           - AssocSplatNode
           - NoKeywordsParameterNode
+        comment: |
+          Represents the rest of the Hash keys and values. This can be named, unnamed, or explicitly forbidden via `**nil`, this last one results in a `NoKeywordsParameterNode`.
+
+              foo => { a: 1, b:, **c }
+                                 ^^^
+
+              foo => { a: 1, b:, ** }
+                                 ^^
+
+              foo => { a: 1, b:, **nil }
+                                 ^^^^^
       - name: opening_loc
         type: location?
+        comment: |
+          The location of the opening brace.
+
+              foo => { a: 1 }
+                     ^
+
+              foo => Bar[a: 1]
+                        ^
       - name: closing_loc
         type: location?
+        comment: |
+          The location of the closing brace.
+
+              foo => { a: 1 }
+                            ^
+
+              foo => Bar[a: 1]
+                             ^
     comment: |
       Represents a hash pattern in pattern matching.
 
@@ -2181,6 +2224,12 @@ nodes:
 
           foo => { a: 1, b: 2, **c }
                  ^^^^^^^^^^^^^^^^^^^
+
+          foo => Bar[a: 1, b: 2]
+                 ^^^^^^^^^^^^^^^
+
+          foo in { a: 1, b: 2 }
+                 ^^^^^^^^^^^^^^
   - name: IfNode
     fields:
       - name: if_keyword_loc