Assistant: Code blocks contain spurious "diagnostics errors"

[jmcphers]

Ask Assistant to generate a plot using ggplot, before loading ggplot2, and you'll probably get something like this:

These are the errors you'd see in an R script that uses ggplot2 if you haven't loaded ggplot2, but adding these diagnostics to code generated by Assistant doesn't make much sense.

These diagnostics are also unhelpful because they are wrong -- since the code contains a library(ggplot2), it will actually run just fine.

There are several ways to address this, but for the short term we should just avoid generating diagnostics for Assistant-generated code blocks.

Related to (but not solved by) #6967.

[rodrigosf672]

Verified Fixed

Positron Version(s) : 2025.07.0 (Universal) build 170
OS Version          : macOS Sequoia 15.5

Test scenario(s)

• No diagnostics errors are yielded by the Assistant
• Helpful clarification that Python doesn't have ggplot natively is provided.