Schema: reuse field specs across nav-item, other-links, code-links

[cderv]

Suggested by @cscheid in #6858 (comment):

Having a schema to document and details "text" specification (and other fields) everywhere from one single file could be a nice future enhancement.

The same fields (text, href, icon, rel, target) appear in several schema definitions with overlapping but independently-maintained descriptions:

quarto-cli/src/resources/schema/definitions.yml

Lines 112 to 178 in 57705c3

	- id: navigation-item-object
	object:
	closed: true
	properties:
	aria-label:
	string:
	description: "Accessible label for the item."
	file:
	hidden: true
	string:
	description: |
	Alias for href
	href:
	string:
	description: |
	Link to file contained with the project or external URL
	icon:
	string:
	description:
	short: Name of bootstrap icon (e.g. `github`, `bluesky`, `share`)
	long: |
	Name of bootstrap icon (e.g. `github`, `bluesky`, `share`)
	See <https://icons.getbootstrap.com/> for a list of available icons
	id:
	# "core identification"
	# this field is only used in typescript
	schema: string
	hidden: true
	menu:
	arrayOf:
	schema:
	ref: navigation-item
	text:
	string:
	description: |
	Text to display for item (defaults to the
	document title if not provided)
	url:
	hidden: true
	string:
	description: |
	Alias for href
	rel:
	string:
	description: |
	Value for rel attribute. Multiple space-separated values are permitted.
	See <https://developer.mozilla.org/en-US/docs/Web/HTML/Attributes/rel>
	for a details.
	target:
	string:
	description: |
	Value for target attribute.
	See <https://developer.mozilla.org/en-US/docs/Web/HTML/Element/a#attr-target>
	for details.
	- id: giscus-themes
	enum:
	values:
	[
	light,
	light_high_contrast,
	light_protanopia,
	light_tritanopia,
	dark,
	dark_high_contrast,
	dark_protanopia,
	dark_tritanopia,

quarto-cli/src/resources/schema/definitions.yml

Lines 1321 to 1340 in 57705c3

	- id: other-links
	arrayOf:
	object:
	properties:
	text:
	string:
	description: "The text for the link."
	href:
	string:
	description: "The href for the link."
	icon:
	string:
	description: "The bootstrap icon name for the link."
	rel:
	string:
	description: "The rel attribute value for the link."
	target:
	string:
	description: "The target attribute value for the link."
	required: [text, href]

quarto-cli/src/resources/schema/definitions.yml

Lines 2493 to 2516 in 57705c3

	- id: code-links-schema
	schema:
	anyOf:
	- boolean
	- maybeArrayOf:
	anyOf:
	- object:
	properties:
	icon:
	string:
	description: The bootstrap icon for this code link.
	text:
	string:
	description: The text for this code link.
	href:
	string:
	description: The href for this code link.
	rel:
	string:
	description: The rel used in the `a` tag for this code link.
	target:
	string:
	description: The target used in the `a` tag for this code link.
	- enum: ["repo", "binder", "devcontainer"]

Drift between these is real. Documenting markdown support on navigation-item.text (#6858) did not propagate to other-links.text or code-links.text, even though all three describe similar link-target text. Same risk for href, icon, rel, target.

We could extract these into reusable schema fragments and reference them from each site, so a single edit updates every place a field is documented.

Opening this to track the idea.