librustc: Forbid .. in range patterns.

This breaks code that looks like:

    match foo {
        1..3 => { ... }
    }

Instead, write:

    match foo {
        1...3 => { ... }
    }

Closes #17295.

[breaking-change]

src/test/compile-fail/refutable-pattern-errors.rs

@@ -9,10 +9,10 @@
 // except according to those terms.
 
 
-fn func((1, (Some(1), 2..3)): (int, (Option<int>, int))) { }
+fn func((1, (Some(1), 2...3)): (int, (Option<int>, int))) { }
 //~^ ERROR refutable pattern in function argument: `(_, _)` not covered
 
 fn main() {
-    let (1i, (Some(1i), 2i..3i)) = (1i, (None, 2i));
+    let (1i, (Some(1i), 2i...3i)) = (1i, (None, 2i));
     //~^ ERROR refutable pattern in local binding: `(_, _)` not covered
 }