Upgrade to Rust 1.86 and bump MSRV to 1.84 (#17171)

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## Summary

I decided to disable the new
[`needless_continue`](https://rust-lang.github.io/rust-clippy/master/index.html#needless_continue)
rule because I often found the explicit `continue` more readable over an
empty block or having to invert the condition of an other branch.


## Test Plan

`cargo test`

---------

Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>

crates/ruff_linter/src/rule_selector.rs

@@ -216,8 +216,7 @@ impl RuleSelector {
                 }
                 // Deprecated rules are excluded in preview mode and with 'All' option unless explicitly selected
                 RuleGroup::Deprecated => {
-                    (!preview_enabled || self.is_exact())
-                        && !matches!(self, RuleSelector::All { .. })
+                    (!preview_enabled || self.is_exact()) && !matches!(self, RuleSelector::All)
                 }
                 // Removed rules are included if explicitly selected but will error downstream
                 RuleGroup::Removed => self.is_exact(),