v3.2: Parameter and Header example updates

[handrews]

Note: This replaces the other half of PR #4673 (the first half being replaced by PR #4800), and updates parameter and header examples for PRs #4800, #4799., and #4802.

This updates for both the new example fields and for examples with content

• no schema changes are needed for this pull request

[handrews]

@ralfhandl the email notification contained this:

In src/oas.md:

@@ -1183,11 +1273,14 @@ content:
schema:
type: string
example: $.a.b[1:1]
+examples:
examples and example can currently only be used with schema, not with content, see https://github.com/OAI/OpenAPI-Specification/blob/v3.2-dev/src/oas.md#fixed-fields-for-use-with-content.

This affects multiple examples :sad:

but I don't see it now... was this just because I had split this from PR #4802? (and accidentally posted them in the wrong order...)

[ralfhandl]

Yes, I got confused for a minute and lost sight of the target picture.