fix: modify assert(x) span to cover entire statement

[TomAFrench]

Description

Problem*

Resolves #3175

Summary*

This PR fixes #3175 but I'm not sure if it's exactly the route we want to go down in general. I'm now setting the span of the constraint's condition to cover the entire statement rather than purely the condition alone. This is consistent with how we handle assert_eq but feels like I'm misusing this.

Perhaps we should assign explicit spans to statements rather than relying on using the spans of their fields.

Documentation

• This PR requires documentation updates when merged.

  • I will submit a noir-lang/docs PR.
  • I will request for and support Dev Rel's help in documenting this PR.

Additional Context

PR Checklist*

• I have tested the changes locally.
• I have formatted the changes with Prettier and/or cargo fmt on default settings.

[jfecher]

Perhaps we should assign explicit spans to statements rather than relying on using the spans of their fields.

I'd be in favor of this approach