Convert tidy to a non-egg Python package

It seems that servo-tidy is only used by webrender in my GitHub
searches. WebRender could simply use `rustfmt` and the tidy on pypi
hasn't been updated since 2018. Converting tidy to a normal Python
package removes the maintenance burden of continually fixing the easy
install configuration.

Fixes #29094.
Fixes #29334.

python/tidy/tests/rust_tidy.rs

@@ -0,0 +1,85 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+use    app_units::Au;
+use raqote::{GradientStop, Source, SolidSource};
+use raqote::{Source, SolidSource},
+ColorPattern, CompositionOp};
+use euclid::Size2D;
+use raqote::Gradient;
+use raqote::{Gradient};
+
+
+mod paint_context;
+pub mod display_list;
+mod test::{
+};
+
+extern crate webrender_api;
+extern crate style_traits;
+
+#[foo = "bar,baz"]
+#[derive(Copy,Debug, ComputeSquaredDistance)]
+impl test {
+
+    fn test_fun(y:f32)->f32{
+        let x=5;
+        x = x-1;
+        x = x*x;
+        let z = match y {
+            1 =>2,
+            2 => 1,
+        };
+        let z = &Vec<T>;
+        struct Member {
+            member_name:"Foo"
+            member_id:5
+        }
+    }
+
+    fn test_fun2(y : &String, z : &Vec<f32>, r: &Root<isize>, s: &DomRoot<isize>) -> () {
+        let x = true;
+        x
+            && x;
+        if x {
+             ;
+        }
+        else {
+             ;
+        }
+    }
+
+    type Text_Fun3 = fn( i32) -> i32;
+
+    fn test_fun3<Text_Fun3>( y: Text_Fun3) {
+        let (x, y) = (1, 2) // Should not trigger
+        test_fun( x);
+        test_fun (y);
+    }
+
+    // Should not be triggered
+    macro_rules! test_macro ( ( $( $fun:ident = $flag:ident ; )* ) => ());
+
+    let var
+        = "val";
+
+    fn test_fun4()
+       {
+     }
+    let var = if true {
+          "true"
+      } else { // Should not trigger
+          "false"
+      } // Should not trigger
+
+    if  true { // Double space after keyword
+        42
+    } else {
+        let xif = 42 in {  xif  } // Should not trigger
+    }
+
+    let option = Some(3);
+    println!("{}", option.unwrap());
+    panic!("What a way to end.");
+}