Correct usage of {{#author}} is being marked as deprecated - GS001-DEPR-AUTHBL

[mneveroff]

Issue Summary

When foregoing author.hbs and using {{#author}} in index.hbs I'm getting an error about this approach being deprecated. Neither of the recommended approaches work, however: {{ log primary_author }} and {{ log authors }} return undefined within that context.

Expectation: Seeing as index.hbs is defined as fallback for author.hbs in the documentation, I would expect this to be a legal usage of the tag.

Suggestion: adjust the deprecation warning on both gscan and ghost run -D Issue: This is preventing me from confidently publishing my theme as the installation contains errors and hampers the user flow.

Steps to Reproduce

1. Clone casper theme
2. Remove authors.hbs
3. Inside index.hbs, add:

{{#is "author"}}
    {{#author}}
        <h1 class="author-name">{{name}}</h1>
    {{/author}}
{{/is}}

The code will work but both gscan and ghost-cli would throw a GS001-DEPR-AUTHBL

Ghost Version

5.79.0

Node.js Version

v18.12.1

How did you install Ghost?

ghost-cli local install

Database type

SQLite3

Browser & OS version

No response

Relevant log / error output

Details:
    checkedVersion: 5.x
    name:           chapter
    path:           /Users/mneveroff/Development/Web/ghost-cli/content/themes/chapter
    version:        1.1.2
    errors: 
      - 
        fatal:      false
        level:      error
        rule:       The <code>{{#author}}</code> block helper should be replaced with <code>{{#primary_author}}</code> or <code>{{#foreach authors}}...{{/foreach}}</code>
        details:    The usage of <code>{{#author}}</code> block helper outside of <code>author.hbs</code> is no longer supported andshould be replaced with <code>{{#primary_author}}</code> or <code>{{#foreach authors}}...{{/foreach}}</code>.<br>Ghost allows multiple authors to be assigned to a post, so all helpers have been reworked to account for this.<br>Find more information about the <code>{{authors}}</code> helper <a href="https://ghost.org/docs/themes/helpers/authors/" target=_blank>here</a>
        regex: 
        notValidIn: author.hbs
        helper:     {{#author}}
        failures: 
          - 
            ref:     index.hbs
            message: Please remove or replace {{#author}} from this template
        code:       GS001-DEPR-AUTHBL
    warnings: 
      (empty array)

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