feat: Add wildcard slice expression support

Implements wildcard slice syntax for arrays and lists:
- arr.[*] selects all elements
- matrix.[0.., *] for multi-dimensional slicing
- Consistent with F# 6.0+ slice syntax

The grammar already supported '*' in slice_range but wasn't creating
a proper AST node. This change aliases '*' as wildcard_slice for
clearer AST representation.

Tests added for:
- Simple wildcard slice: arr.[*]
- 2D array row slice: matrix.[0.., *]
- 2D array column slice: matrix.[*, 0..]

Author: NatElkins

fsharp/grammar.js

@@ -987,7 +987,7 @@ module.exports = grammar({
         ),
       ),
 
-    slice_range: ($) => choice($._slice_range_special, $._expression, "*"),
+    slice_range: ($) => choice($._slice_range_special, $._expression, alias("*", $.wildcard_slice)),
 
     //
     // Computation expression (END)

fsharp/src/grammar.json

@@ -3375,8 +3375,13 @@
           "name": "_expression"
         },
         {
-          "type": "STRING",
-          "value": "*"
+          "type": "ALIAS",
+          "content": {
+            "type": "STRING",
+            "value": "*"
+          },
+          "named": true,
+          "value": "wildcard_slice"
         }
       ]
     },

fsharp/src/node-types.json

@@ -3160,6 +3160,10 @@
         {
           "type": "_expression",
           "named": true
+        },
+        {
+          "type": "wildcard_slice",
+          "named": true
         }
       ]
     }
@@ -4522,11 +4526,11 @@
   },
   {
     "type": "unit",
-    "named": true
+    "named": false
   },
   {
     "type": "unit",
-    "named": false
+    "named": true
   },
   {
     "type": "unmanaged",
@@ -4576,6 +4580,10 @@
     "type": "wildcard_pattern",
     "named": true
   },
+  {
+    "type": "wildcard_slice",
+    "named": true
+  },
   {
     "type": "with",
     "named": false