Merge pull request #4856 from backstage/docs/custom-action

docs: updating the example action to be valid typescript

docs/features/software-templates/writing-custom-actions.md

@@ -19,7 +19,7 @@ passed as `input` to the function.
 In `packages/backend/src/actions/custom.ts` we can create a new action.
 
 ```ts
-import { createTemplateAction } from '../../createTemplateAction';
+import { createTemplateAction } from '@backstage/plugin-scaffolder-backend';
 import fs from 'fs-extra';
 
 export const createNewFileAction = () => {
@@ -35,7 +35,7 @@ export const createNewFileAction = () => {
             title: 'Contents',
             description: 'The contents of the file',
           },
-          contents: {
+          filename: {
             type: 'string',
             title: 'Filename',
             description: 'The filename of the file that will be created',
@@ -46,7 +46,7 @@ export const createNewFileAction = () => {
     async handler(ctx) {
       await fs.outputFile(
         `${ctx.workspacePath}/${ctx.input.filename}`,
-        ctx.input.content,
+        ctx.input.contents,
       );
     },
   });