Proofread instrument descriptions (briefs) for http.(client|server).request.duration

[trask]

While instrument descriptions are allowed to change after stability (https://github.com/open-telemetry/opentelemetry-specification/blob/v1.20.0/specification/versioning-and-stability.md#semantic-conventions-stability), changing them does have some undesirable impact: open-telemetry/opentelemetry-demo#969

[trask]

What should we do about briefs that have markdown? e.g.

HTTP response status code.

Options:

• (a) Move the links to the note section
• (b) Include language somewhere that metric instrument briefs should include only the textual portion, excluding markdown
• (c) Include language somewhere clarifying that metric instrument briefs should be the exact string, including markdown

(oops, see below, there is no markdown in the above instrument briefs at least)

[trask]

OOOPS! I got confused. It's only instrument descriptions (briefs) which cause these warnings, and not attribute briefs.