DOC-13911: Migrate OpenAPI Generator templates to Handlebars

[simon-dew]

Docs issue: DOC-13911

Replaces the openapi-generator mustache templates with handlebars templates.

The functionality and structure of the templates is pretty much the same. The main differences are:

• I can't get the mustache lambdas to work, which means some headings have different casing, e.g. camel case instead of separate words.
• I can't get the templates to detect whether partial files exist or not. As a fallback, the output document attempts to include every single possible partial, using the AsciiDoc optional option. If the partial does not exist it is simply not displayed.
• The templates now impose a hierarchy on the model definitions: those which are referenced directly from an operation request or response are heading 3, whereas models which are only referenced from other models are heading 4 and are excluded from the right-hand nav to save space.
• There is still some ifdef, ifndef, and ifeval logic in the output doc. It may be possible to get rid of these with handlebars helpers, but that's beyond me for the present.

Note for reviewers: I'm not expecting you to go through the handlebars with a fine-tooth comb, but it would be great if you wanted to do that. What I suggest is that you look at the output index.adoc files. You should see that they are pretty much the same, with mostly only spacing differences and differences as noted above.

Doc previews:

• Query Service APIs and following
• Index Service APIs and following
• Search Service APIs and following
• Eventing Service API
• Analytics REST APIs and following

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[Copilot]

Pull request overview

This PR migrates OpenAPI Generator templates from Mustache to Handlebars across all REST API documentation modules in the Couchbase server documentation.

Changes:

• Adds engine = "handlebars" configuration to all Gradle build files that generate OpenAPI documentation
• Updates generated AsciiDoc index files with formatting changes, including removal of commented-out "markup not found" lines
• Adds nullable: true property to specific schema fields in analytics-links.yaml

Reviewed changes

Copilot reviewed 30 out of 62 changed files in this pull request and generated 14 comments.

File	Description
*.gradle	Adds handlebars engine configuration to OpenAPI generation tasks
*/pages/index.adoc	Regenerated documentation with handlebars templates, removing placeholder comments and adjusting spacing
analytics-links.yaml	Marks alternateAddresses and hostname fields as nullable

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[osfameron]

Looks promising!

It looks like OG uses https://javadoc.io/doc/com.github.jknack/handlebars/4.0.6/com/github/jknack/handlebars/helper/StringHelpers.html which has lower but obviously nothing as useful as a camelCase function 😡 😡 😡 wtf.

Obviously fixing that is trivial if we move to OG+ wholesale.
Otherwise, we could simply use the OG logic to export a raw JSON, and then write our own simple Handlebars renderer in JS.

[simon-dew]

It looks like OG uses https://javadoc.io/doc/com.github.jknack/handlebars/4.0.6/com/github/jknack/handlebars/helper/StringHelpers.html which has lower but obviously nothing as useful as a camelCase function 😡 😡 😡 wtf.

Thank you, that was actually very helpful.

[osfameron]

"Close enough for jazz!" 🎶 🎷