fix: Support line continuations in TQ_extra_instructions & placeholders

[claremacrae]

Types of changes

Changes visible to users:

• Bug fix (prefix: fix - non-breaking change which fixes an issue)
  • Issue/discussion: None, but it fixes a limitation that was mentioned in the TQ_extra_instructions docs
• Documentation (prefix: docs - improvements to any documentation content for users)

Internal changes:

• Tests (prefix: test - additions and improvements to unit tests and the smoke tests)

Description

Fix a documented limitation that instructions in TQ_extra_instructions and in multi-line placeholders did not support line continuations.

Motivation and Context

I am addressing limitations in the forthcoming "includes" feature (that is its current working name - I don't yet know what the finale name will be.)

How has this been tested?

• Updating existing unit tests
• Manual exploratory testing

Screenshots (if appropriate)

Here is an example Markdown file that now works:

---
task_instructions_with_continuation_line: |-
  path \
    includes query_using_properties
---
# Test

```tasks
explain
{{query.file.property('task_instructions_with_continuation_line')}}
```

Before, it gave an error:

Now it works:

That used a placeholder, but the same improvements improve the behaviour of TQ_extra_instructions.

Checklist

• My code follows the code style of this project and passes yarn run lint.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• My change has adequate Unit Test coverage.

Terms

• My contribution follows this project's contributing guide
• I agree to follow this project's Code of Conduct

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud