migrate to new mutable decl syntax

std/meta/meta.hon

@@ -46,9 +46,9 @@ TypeInfo :: union(enum) {
 EnumFieldStruct proc($E, $Field type, $default ?Field) type {
     match typeinfo!(E) {
         .enum |info|: {
-            names [info.fields.len]mut []u8 = undefined
-            field_types [info.fields.len]mut type = undefined
-            defaults [info.fields.len]mut ?Field = undefined
+            names [info.fields.len]mut []u8 := undefined
+            field_types [info.fields.len]mut type := undefined
+            defaults [info.fields.len]mut ?Field := undefined
             inline for info.fields |field, index| {
                 names[index] = field.name
                 field_types[index] = Field

std/meta/meta.test.hon

@@ -42,7 +42,7 @@ distinct_reflection_exposes_immediate_backing test {
 
 
 enum_field_struct_defaults test {
-    names TestNames = {
+    names TestNames := {
         ident = "identifier",
         int = "integer",
     }
@@ -60,7 +60,7 @@ enum_field_struct_defaults test {
         try testing.expect(false)
     }
 
-    empty TestNames = {}
+    empty TestNames := {}
     if field!(empty, "ident") |_| {
         try testing.expect(false)
     }