Lifetimes UI test cleanup

* Removes an unneeded `#![warn(clippy::extra_unused_lifetimes)]` from
  the `needless_lifetimes` test - the tests for those are in a different
  file.

* Renames `unused_lt.{rs,stderr}` to `extra_unused_lifetimes.{rs,stderr}`
* Renames `lifetimes.{rs,stderr}` to `needless_lifetimes.{rs,stderr}`

tests/ui/extra_unused_lifetimes.stderr

@@ -1,5 +1,5 @@
 error: this lifetime isn't used in the function definition
-  --> $DIR/unused_lt.rs:14:14
+  --> $DIR/extra_unused_lifetimes.rs:14:14
    |
 LL | fn unused_lt<'a>(x: u8) {}
    |              ^^
@@ -7,13 +7,13 @@ LL | fn unused_lt<'a>(x: u8) {}
    = note: `-D clippy::extra-unused-lifetimes` implied by `-D warnings`
 
 error: this lifetime isn't used in the function definition
-  --> $DIR/unused_lt.rs:16:25
+  --> $DIR/extra_unused_lifetimes.rs:16:25
    |
 LL | fn unused_lt_transitive<'a, 'b: 'a>(x: &'b u8) {
    |                         ^^
 
 error: this lifetime isn't used in the function definition
-  --> $DIR/unused_lt.rs:41:10
+  --> $DIR/extra_unused_lifetimes.rs:41:10
    |
 LL |     fn x<'a>(&self) {}
    |          ^^

tests/ui/needless_lifetimes.rs

@@ -1,4 +1,4 @@
-#![warn(clippy::needless_lifetimes, clippy::extra_unused_lifetimes)]
+#![warn(clippy::needless_lifetimes)]
 #![allow(dead_code, clippy::needless_pass_by_value, clippy::trivially_copy_pass_by_ref)]
 
 fn distinct_lifetimes<'a, 'b>(_x: &'a u8, _y: &'b u8, _z: u8) {}

tests/ui/needless_lifetimes.stderr

@@ -1,5 +1,5 @@
 error: explicit lifetimes given in parameter types where they could be elided (or replaced with `'_` if needed by type declaration)
-  --> $DIR/lifetimes.rs:4:1
+  --> $DIR/needless_lifetimes.rs:4:1
    |
 LL | fn distinct_lifetimes<'a, 'b>(_x: &'a u8, _y: &'b u8, _z: u8) {}
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
@@ -7,13 +7,13 @@ LL | fn distinct_lifetimes<'a, 'b>(_x: &'a u8, _y: &'b u8, _z: u8) {}
    = note: `-D clippy::needless-lifetimes` implied by `-D warnings`
 
 error: explicit lifetimes given in parameter types where they could be elided (or replaced with `'_` if needed by type declaration)
-  --> $DIR/lifetimes.rs:6:1
+  --> $DIR/needless_lifetimes.rs:6:1
    |
 LL | fn distinct_and_static<'a, 'b>(_x: &'a u8, _y: &'b u8, _z: &'static u8) {}
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: explicit lifetimes given in parameter types where they could be elided (or replaced with `'_` if needed by type declaration)
-  --> $DIR/lifetimes.rs:16:1
+  --> $DIR/needless_lifetimes.rs:16:1
    |
 LL | / fn in_and_out<'a>(x: &'a u8, _y: u8) -> &'a u8 {
 LL | |     x
@@ -21,7 +21,7 @@ LL | | }
    | |_^
 
 error: explicit lifetimes given in parameter types where they could be elided (or replaced with `'_` if needed by type declaration)
-  --> $DIR/lifetimes.rs:45:1
+  --> $DIR/needless_lifetimes.rs:45:1
    |
 LL | / fn deep_reference_3<'a>(x: &'a u8, _y: u8) -> Result<&'a u8, ()> {
 LL | |     Ok(x)
@@ -29,7 +29,7 @@ LL | | }
    | |_^
 
 error: explicit lifetimes given in parameter types where they could be elided (or replaced with `'_` if needed by type declaration)
-  --> $DIR/lifetimes.rs:50:1
+  --> $DIR/needless_lifetimes.rs:50:1
    |
 LL | / fn where_clause_without_lt<'a, T>(x: &'a u8, _y: u8) -> Result<&'a u8, ()>
 LL | | where
@@ -40,13 +40,13 @@ LL | | }
    | |_^
 
 error: explicit lifetimes given in parameter types where they could be elided (or replaced with `'_` if needed by type declaration)
-  --> $DIR/lifetimes.rs:62:1
+  --> $DIR/needless_lifetimes.rs:62:1
    |
 LL | fn lifetime_param_2<'a, 'b>(_x: Ref<'a>, _y: &'b u8) {}
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: explicit lifetimes given in parameter types where they could be elided (or replaced with `'_` if needed by type declaration)
-  --> $DIR/lifetimes.rs:86:1
+  --> $DIR/needless_lifetimes.rs:86:1
    |
 LL | / fn fn_bound_2<'a, F, I>(_m: Lt<'a, I>, _f: F) -> Lt<'a, I>
 LL | | where
@@ -57,7 +57,7 @@ LL | | }
    | |_^
 
 error: explicit lifetimes given in parameter types where they could be elided (or replaced with `'_` if needed by type declaration)
-  --> $DIR/lifetimes.rs:120:5
+  --> $DIR/needless_lifetimes.rs:120:5
    |
 LL | /     fn self_and_out<'s>(&'s self) -> &'s u8 {
 LL | |         &self.x
@@ -65,13 +65,13 @@ LL | |     }
    | |_____^
 
 error: explicit lifetimes given in parameter types where they could be elided (or replaced with `'_` if needed by type declaration)
-  --> $DIR/lifetimes.rs:129:5
+  --> $DIR/needless_lifetimes.rs:129:5
    |
 LL |     fn distinct_self_and_in<'s, 't>(&'s self, _x: &'t u8) {}
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 error: explicit lifetimes given in parameter types where they could be elided (or replaced with `'_` if needed by type declaration)
-  --> $DIR/lifetimes.rs:148:1
+  --> $DIR/needless_lifetimes.rs:148:1
    |
 LL | / fn struct_with_lt<'a>(_foo: Foo<'a>) -> &'a str {
 LL | |     unimplemented!()
@@ -79,7 +79,7 @@ LL | | }
    | |_^
 
 error: explicit lifetimes given in parameter types where they could be elided (or replaced with `'_` if needed by type declaration)
-  --> $DIR/lifetimes.rs:178:1
+  --> $DIR/needless_lifetimes.rs:178:1
    |
 LL | / fn trait_obj_elided2<'a>(_arg: &'a Drop) -> &'a str {
 LL | |     unimplemented!()
@@ -87,7 +87,7 @@ LL | | }
    | |_^
 
 error: explicit lifetimes given in parameter types where they could be elided (or replaced with `'_` if needed by type declaration)
-  --> $DIR/lifetimes.rs:184:1
+  --> $DIR/needless_lifetimes.rs:184:1
    |
 LL | / fn alias_with_lt<'a>(_foo: FooAlias<'a>) -> &'a str {
 LL | |     unimplemented!()
@@ -95,7 +95,7 @@ LL | | }
    | |_^
 
 error: explicit lifetimes given in parameter types where they could be elided (or replaced with `'_` if needed by type declaration)
-  --> $DIR/lifetimes.rs:203:1
+  --> $DIR/needless_lifetimes.rs:203:1
    |
 LL | / fn named_input_elided_output<'a>(_arg: &'a str) -> &str {
 LL | |     unimplemented!()
@@ -103,7 +103,7 @@ LL | | }
    | |_^
 
 error: explicit lifetimes given in parameter types where they could be elided (or replaced with `'_` if needed by type declaration)
-  --> $DIR/lifetimes.rs:211:1
+  --> $DIR/needless_lifetimes.rs:211:1
    |
 LL | / fn trait_bound_ok<'a, T: WithLifetime<'static>>(_: &'a u8, _: T) {
 LL | |     unimplemented!()
@@ -111,7 +111,7 @@ LL | | }
    | |_^
 
 error: explicit lifetimes given in parameter types where they could be elided (or replaced with `'_` if needed by type declaration)
-  --> $DIR/lifetimes.rs:247:1
+  --> $DIR/needless_lifetimes.rs:247:1
    |
 LL | / fn out_return_type_lts<'a>(e: &'a str) -> Cow<'a> {
 LL | |     unimplemented!()