fix(es/codegen): Mark bigint as an item starting with number (#5207)

crates/swc/tests/fixture/issues-5xxx/5206/input/.swcrc

@@ -0,0 +1,19 @@
+{
+    "jsc": {
+        "parser": {
+            "syntax": "ecmascript",
+            "jsx": false
+        },
+        "target": "es2022",
+        "loose": false,
+        "minify": {
+            "compress": false,
+            "mangle": false
+        }
+    },
+    "module": {
+        "type": "es6"
+    },
+    "minify": true,
+    "isModule": true
+}

crates/swc/tests/fixture/issues-5xxx/5206/input/index.js

@@ -0,0 +1,3 @@
+function zero() {
+    return 0n
+}

crates/swc/tests/fixture/issues-5xxx/5206/output/index.js

@@ -0,0 +1 @@
+function zero(){return 0n}

crates/swc_ecma_codegen/src/util.rs

@@ -74,6 +74,7 @@ impl StartsWithAlphaNum for Expr {
             | Expr::Lit(Lit::Bool(_))
             | Expr::Lit(Lit::Num(_))
             | Expr::Lit(Lit::Null(_))
+            | Expr::Lit(Lit::BigInt(_))
             | Expr::Await(_)
             | Expr::Fn(_)
             | Expr::Class(_)