Update shebang reference rule names

This updates the rule names for shebang which were changed in
rust-lang/reference#2192 and rust-lang/reference#2199.

Author: ehuss

tests/ui/parser/shebang/issue-71471-ignore-tidy.rs

@@ -1,4 +1,4 @@
 
 #!B //~ ERROR expected `[`, found `B`
 
-//@ reference: input.shebang
+//@ reference: shebang.position

tests/ui/parser/shebang/shebang-comment.rs

@@ -1,7 +1,7 @@
 #!//bin/bash
 
 //@ check-pass
-//@ reference: input.shebang
+//@ reference: shebang.syntax
 fn main() {
     println!("a valid shebang (that is also a rust comment)")
 }

tests/ui/parser/shebang/shebang-empty.rs

@@ -1,5 +1,5 @@
 #!
 
 //@ check-pass
-//@ reference: input.shebang
+//@ reference: shebang.syntax
 fn main() {}

tests/ui/parser/shebang/shebang-must-start-file.rs

@@ -1,7 +1,7 @@
 // something on the first line for tidy
 #!/bin/bash  //~ ERROR expected `[`, found `/`
 
-//@ reference: input.shebang
+//@ reference: shebang.position
 
 fn main() {
     println!("ok!");

tests/ui/parser/shebang/shebang-space.rs

@@ -1,6 +1,6 @@
 #!    
 
 //@ check-pass
-//@ reference: input.shebang
+//@ reference: shebang.syntax
 // ignore-tidy-end-whitespace
 fn main() {}

tests/ui/parser/shebang/valid-shebang.rs

@@ -1,7 +1,7 @@
 #!/usr/bin/env run-cargo-script
 
 //@ check-pass
-//@ reference: input.shebang
+//@ reference: shebang.syntax
 fn main() {
     println!("Hello World!");
 }