Describe the bug

The context sub cammand in cdk cli says it requests the --app parameter, but it doesn't.

Help Command:
cdk context help

Output:

cdk context

Manage cached context values

Options:
  -a, --app                REQUIRED: command-line for executing your app or a
                           cloud assembly directory (e.g. "node bin/my-app.js")
                                                                        [string]

Context Command:
cdk context --json

Output:

{
 "myKey": "MyValue"
}

Expected Behavior

Either --app should be required or the help should say it's optional

Current Behavior

--app is optional but the help says its required

Reproduction Steps

cdk context --json

Possible Solution

No response

Additional Information/Context

No response

CDK CLI Version

2.31.1

Framework Version

No response

Node.js Version

14

OS

AL2

Language

Typescript

Language Version

typescript (4.0)

Other information

No response