Add keyword_loc to ForwardingSuperNode

They can take a block and so the keyword location is not always the entirety of the node.
You can get it by constructing a location that is just the first 5 characters
but why not have it be provided by prism?

Author: Earlopain

config.yml

@@ -2627,6 +2627,14 @@ nodes:
           end
   - name: ForwardingSuperNode
     fields:
+      - name: keyword_loc
+        type: location
+        comment: |
+          super
+          ^^^^^
+
+          super { 123 }
+          ^^^^^
       - name: block
         type: node?
         kind: BlockNode

snapshots/super.txt

@@ -7,6 +7,7 @@
     └── body: (length: 9)
         ├── @ ForwardingSuperNode (location: (1,0)-(1,5))
         │   ├── flags: newline
+        │   ├── keyword_loc: (1,0)-(1,5) = "super"
         │   └── block: ∅
         ├── @ SuperNode (location: (3,0)-(3,7))
         │   ├── flags: newline
@@ -83,6 +84,7 @@
         │       └── operator_loc: (11,6)-(11,7) = "&"
         ├── @ ForwardingSuperNode (location: (13,0)-(13,8))
         │   ├── flags: newline
+        │   ├── keyword_loc: (13,0)-(13,5) = "super"
         │   └── block:
         │       @ BlockNode (location: (13,6)-(13,8))
         │       ├── flags: ∅

snapshots/unparser/corpus/literal/super.txt

@@ -7,6 +7,7 @@
     └── body: (length: 11)
         ├── @ ForwardingSuperNode (location: (1,0)-(1,5))
         │   ├── flags: newline
+        │   ├── keyword_loc: (1,0)-(1,5) = "super"
         │   └── block: ∅
         ├── @ SuperNode (location: (2,0)-(2,7))
         │   ├── flags: newline
@@ -170,6 +171,7 @@
         │   └── block: ∅
         ├── @ ForwardingSuperNode (location: (10,0)-(12,1))
         │   ├── flags: newline
+        │   ├── keyword_loc: (10,0)-(10,5) = "super"
         │   └── block:
         │       @ BlockNode (location: (10,6)-(12,1))
         │       ├── flags: ∅

snapshots/whitequark/super_block.txt

@@ -7,6 +7,7 @@
     └── body: (length: 2)
         ├── @ ForwardingSuperNode (location: (1,0)-(1,12))
         │   ├── flags: newline
+        │   ├── keyword_loc: (1,0)-(1,5) = "super"
         │   └── block:
         │       @ BlockNode (location: (1,6)-(1,12))
         │       ├── flags: ∅

snapshots/whitequark/zsuper.txt

@@ -7,4 +7,5 @@
     └── body: (length: 1)
         └── @ ForwardingSuperNode (location: (1,0)-(1,5))
             ├── flags: newline
+            ├── keyword_loc: (1,0)-(1,5) = "super"
             └── block: ∅

src/prism.c

@@ -4379,6 +4379,7 @@ pm_forwarding_super_node_create(pm_parser_t *parser, const pm_token_t *token, pm
         ++parser->node_id,
         0,
         (block == NULL) ? PM_LOCATION_INIT_TOKEN(parser, token) : PM_LOCATION_INIT_TOKEN_NODE(parser, token, block),
+        PM_LOCATION_INIT_TOKEN(parser, token),
         block
     );
 }