better parser errors

error_test/parser/enum_errors.sui

@@ -0,0 +1,29 @@
+# Enum syntax errors
+
+# Missing enum name
+enum
+    Red
+    Green
+end
+
+# Missing variant name
+enum Color
+    Red
+    Green
+end
+
+# Invalid variant syntax (missing parentheses for tuple variant)
+enum Result
+    Ok int
+    Err string
+end
+
+# Missing comma between variants
+enum Color
+    Red Green
+end
+
+# Missing end keyword
+enum Color
+    Red
+    Green