Update coding-style.md

[tonyhallett]

#68238

[Copilot]

Pull Request Overview

This PR refines the wording of the coding-style guideline around using var to make it clear that its use is allowed but not mandatory.

• Rule 10 is updated to “permit” rather than “use” var, emphasizing it’s optional.
• Adjusts parenthetical phrasing for clarity.

Comments suppressed due to low confidence (1)

docs/coding-guidelines/coding-style.md:22

• [nitpick] Consider rephrasing for readability and grammatical correctness, e.g.:

"10. We permit (but do not enforce) var when the type is explicitly named on the right-hand side…"

10. We only permit ( not enforce ) `var` when the type is explicitly named on the right-hand side, typically due to either `new` or an explicit cast, e.g. `var stream = new FileStream(...)` not `var stream = OpenStandardInput()`.

[stephentoub]

Thanks

[stephentoub]

/ba-g hung