[Docs]: Invoke operation isn't correctly described

[Vadym79]

Issue

instead of:
Core Operations
Invoke - Call other durable functions

the correct description is:
Core Operations
Invoke - Call other Lambda functions

as a normal Lambda function can be invoked. Not quite sure, whether I can invoke durable functions.

Page/Location

https://github.com/aws/aws-durable-execution-sdk-java#documentation

Suggested Fix

the correct description is:
Core Operations
Invoke - Call other Lambda functions

as a normal Lambda function can be invoked. Not quite sure, whether I can invoke durable functions.

[zhongkechen]

@Vadym79 thank you for catching and reporting this. I submitted a PR for this: #511