fix(es/codegen): Fix codegen of async methods with decorators (#8575)

**Related issue:**

 - Closes #4311

Author: kdy1

crates/swc/tests/fixture/issues-4xxx/4311/input/.swcrc

@@ -0,0 +1,22 @@
+{
+    "jsc": {
+        "parser": {
+            "syntax": "typescript",
+            "decorators": true,
+            "tsx": false,
+            "keepClassNames": true
+        },
+        "target": "es2020",
+        "preserveAllComments": true,
+        "loose": false,
+        "minify": {
+            "compress": false,
+            "mangle": false
+        }
+    },
+    "module": {
+        "type": "commonjs"
+    },
+    "minify": false,
+    "isModule": true
+}

crates/swc/tests/fixture/issues-4xxx/4311/input/1.js

@@ -0,0 +1,24 @@
+const printMemberName = (target: any, memberName: string) => {
+    console.log(memberName);
+};
+
+class TestClass {
+
+
+    // moving the decorator below the comment works as expected
+
+    @printMemberName
+    /**
+     * some tsdoc comments
+     * 
+     * Some more comments
+     * over
+     * multiple
+     * lines
+     */
+    async run(): Promise<boolean> {
+        return await Promise.resolve(true);
+    }
+}
+
+export { TestClass };

crates/swc/tests/fixture/issues-4xxx/4311/output/1.js

@@ -0,0 +1,30 @@
+"use strict";
+Object.defineProperty(exports, "__esModule", {
+    value: true
+});
+Object.defineProperty(exports, "TestClass", {
+    enumerable: true,
+    get: function() {
+        return TestClass;
+    }
+});
+const _ts_decorate = require("@swc/helpers/_/_ts_decorate");
+const printMemberName = (target, memberName)=>{
+    console.log(memberName);
+};
+class TestClass {
+    // moving the decorator below the comment works as expected
+    /**
+     * some tsdoc comments
+     * 
+     * Some more comments
+     * over
+     * multiple
+     * lines
+     */ async run() {
+        return await Promise.resolve(true);
+    }
+}
+_ts_decorate._([
+    printMemberName
+], TestClass.prototype, "run", null);

crates/swc_ecma_codegen/src/lib.rs

@@ -1474,6 +1474,8 @@ where
     fn emit_class_method(&mut self, n: &ClassMethod) -> Result {
         self.emit_leading_comments_of_span(n.span(), false)?;
 
+        self.emit_leading_comments_of_span(n.key.span(), false)?;
+
         srcmap!(n, true);
 
         for d in &n.function.decorators {