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_python_semantic/src/analyze/function_type.rs

@@ -27,7 +27,7 @@ pub fn classify(
 ) -> FunctionType {
     if !parent_scope.kind.is_class() {
         return FunctionType::Function;
-    };
+    }
     if decorator_list
         .iter()
         .any(|decorator| is_static_method(decorator, semantic, staticmethod_decorators))

crates/ruff_python_semantic/src/analyze/typing.rs

@@ -1231,7 +1231,7 @@ fn match_target<'a>(binding: &Binding, targets: &[Expr], values: &'a [Expr]) ->
                         }
                     }
                     _ => (),
-                };
+                }
             }
             Expr::Name(name) => {
                 if name.range() == binding.range() {