Add tasks names to completions script

[Lispython]

Describe the issue:

• [ ] Bug
• [ ] Change request
• [x] New feature request
• [ ] Discussion request

Issue long description:

Then we use completions for shell we want to complete task name too. Current version supports only completion for devrc flags and options.

Operating system:

Devrc version:

Steps to reproduce:

Current behavior:

Expected behavior:

Additional information:

Mentions: