feat: expand nominal inline match arms

source/diagnostics/diagnostics.hon

@@ -88,6 +88,8 @@ Code :: enum {
     non_exhaustive_match
     unreachable_match_arm
     invalid_match_capture
+    invalid_inline_match_subject
+    invalid_inline_match_capture
     inactive_union_field
     invalid_pointer_type
     invalid_address_operand
@@ -226,6 +228,8 @@ messages :: $enummap.init(Code, []u8, {
     non_exhaustive_match = "match is not exhaustive",
     unreachable_match_arm = "match arm is unreachable",
     invalid_match_capture = "payload capture requires compatible nonvoid tagged union variants",
+    invalid_inline_match_subject = "inline match arm requires an enum or tagged union",
+    invalid_inline_match_capture = "inline match arm requires one enum capture or one payload capture and an optional tag",
     inactive_union_field = "tagged union field is not active",
     invalid_pointer_type = "pointer requires a supported concrete pointee type",
     invalid_address_operand = "address-of requires addressable storage",