fix(packages/codegen): fix printing negative BigIntLiteral after - (#27377)

Fix printing a negative `BigIntLiteral` after `-`.

```javascript
// Original
x = -(-1n);
// Printed - syntax error
x = --1n;
```

This bug could not be produced by an AST which has come from parser, because parser would parse the input as equivalent to `x = -(-(1n));`. But it could be produced when printing a hand-built AST.

packages/codegen/src-js/print/literal.ts

@@ -190,17 +190,25 @@ function printRegExpLiteral(node: ESTree.RegExpLiteral, state: State): void {
 /**
  * Print a bigint literal, parenthesizing a negative one where the position needs it,
  * same as `printNumericLiteral` does.
+ *
+ * Also like `printNumericLiteral`, a negative one is spaced off a preceding `-` or `--`
+ * the same way a unary minus is, so `-(-1n)` prints as `- -1n`, not `--1n`.
  */
 function printBigIntLiteral(node: ESTree.BigIntLiteral, state: State, precedence: number): void {
-  printSpaceBeforeIdentifier(state);
-
   const value = node.bigint;
-  if (value.startsWith("-") && precedence >= PREC_PREFIX) {
-    writeWithMapNoLast(state, "(", node.start, node.end, node);
-    writeNoLast(state, value);
-    write(state, "n)", CAT_CLOSE_BRACKET);
+  if (value.startsWith("-")) {
+    if (precedence >= PREC_PREFIX) {
+      writeWithMapNoLast(state, "(", node.start, node.end, node);
+      writeNoLast(state, value);
+      write(state, "n)", CAT_CLOSE_BRACKET);
+      return;
+    }
+
+    printSpaceBeforeOperator(state, CAT_OP_UN_NEG);
   } else {
-    writeWithMapNoLast(state, value, node.start, node.end, node);
-    writeIdent(state, "n");
+    printSpaceBeforeIdentifier(state);
   }
+
+  writeWithMapNoLast(state, value, node.start, node.end, node);
+  writeIdent(state, "n");
 }

packages/codegen/test/print.test.ts

@@ -352,6 +352,8 @@ describe("unary and update expressions", () => {
     ["delete-infinity", e(unary("delete", num(Infinity))), "delete (0, Infinity);\n"],
     ["minus-negative-literal", e(unary("-", num(-1))), "- -1;\n"],
     ["plus-negative-literal", e(unary("+", num(-1))), "+-1;\n"],
+    ["minus-negative-bigint", e(unary("-", big("-1"))), "- -1n;\n"],
+    ["plus-negative-bigint", e(unary("+", big("-1"))), "+-1n;\n"],
     ["preinc", e(update("++", id("x"))), "++x;\n"],
     ["postinc", e(update("++", id("x"), false)), "x++;\n"],
     ["predec", e(update("--", id("x"))), "--x;\n"],