Bless all let_underscore tests

Author: SquareMan

clippy_lints/foo.txt

@@ -0,0 +1 @@
+Hello

tests/ui/let_underscore_lock.stderr

@@ -1,4 +1,4 @@
-error: non-binding let on a synchronization lock
+error: non-binding `let` on a synchronization lock
   --> $DIR/let_underscore_lock.rs:9:5
    |
 LL |     let _ = p_m.lock();
@@ -7,23 +7,23 @@ LL |     let _ = p_m.lock();
    = help: consider using an underscore-prefixed named binding or dropping explicitly with `std::mem::drop`
    = note: `-D clippy::let-underscore-lock` implied by `-D warnings`
 
-error: non-binding let on a synchronization lock
+error: non-binding `let` on a synchronization lock
   --> $DIR/let_underscore_lock.rs:12:5
    |
 LL |     let _ = p_m1.lock();
    |     ^^^^^^^^^^^^^^^^^^^^
    |
    = help: consider using an underscore-prefixed named binding or dropping explicitly with `std::mem::drop`
 
-error: non-binding let on a synchronization lock
+error: non-binding `let` on a synchronization lock
   --> $DIR/let_underscore_lock.rs:15:5
    |
 LL |     let _ = p_rw.read();
    |     ^^^^^^^^^^^^^^^^^^^^
    |
    = help: consider using an underscore-prefixed named binding or dropping explicitly with `std::mem::drop`
 
-error: non-binding let on a synchronization lock
+error: non-binding `let` on a synchronization lock
   --> $DIR/let_underscore_lock.rs:16:5
    |
 LL |     let _ = p_rw.write();

tests/ui/let_underscore_must_use.stderr

@@ -1,4 +1,4 @@
-error: non-binding let on a result of a `#[must_use]` function
+error: non-binding `let` on a result of a `#[must_use]` function
   --> $DIR/let_underscore_must_use.rs:67:5
    |
 LL |     let _ = f();
@@ -7,87 +7,87 @@ LL |     let _ = f();
    = help: consider explicitly using function result
    = note: `-D clippy::let-underscore-must-use` implied by `-D warnings`
 
-error: non-binding let on an expression with `#[must_use]` type
+error: non-binding `let` on an expression with `#[must_use]` type
   --> $DIR/let_underscore_must_use.rs:68:5
    |
 LL |     let _ = g();
    |     ^^^^^^^^^^^^
    |
    = help: consider explicitly using expression value
 
-error: non-binding let on a result of a `#[must_use]` function
+error: non-binding `let` on a result of a `#[must_use]` function
   --> $DIR/let_underscore_must_use.rs:70:5
    |
 LL |     let _ = l(0_u32);
    |     ^^^^^^^^^^^^^^^^^
    |
    = help: consider explicitly using function result
 
-error: non-binding let on a result of a `#[must_use]` function
+error: non-binding `let` on a result of a `#[must_use]` function
   --> $DIR/let_underscore_must_use.rs:74:5
    |
 LL |     let _ = s.f();
    |     ^^^^^^^^^^^^^^
    |
    = help: consider explicitly using function result
 
-error: non-binding let on an expression with `#[must_use]` type
+error: non-binding `let` on an expression with `#[must_use]` type
   --> $DIR/let_underscore_must_use.rs:75:5
    |
 LL |     let _ = s.g();
    |     ^^^^^^^^^^^^^^
    |
    = help: consider explicitly using expression value
 
-error: non-binding let on a result of a `#[must_use]` function
+error: non-binding `let` on a result of a `#[must_use]` function
   --> $DIR/let_underscore_must_use.rs:78:5
    |
 LL |     let _ = S::h();
    |     ^^^^^^^^^^^^^^^
    |
    = help: consider explicitly using function result
 
-error: non-binding let on an expression with `#[must_use]` type
+error: non-binding `let` on an expression with `#[must_use]` type
   --> $DIR/let_underscore_must_use.rs:79:5
    |
 LL |     let _ = S::p();
    |     ^^^^^^^^^^^^^^^
    |
    = help: consider explicitly using expression value
 
-error: non-binding let on a result of a `#[must_use]` function
+error: non-binding `let` on a result of a `#[must_use]` function
   --> $DIR/let_underscore_must_use.rs:81:5
    |
 LL |     let _ = S::a();
    |     ^^^^^^^^^^^^^^^
    |
    = help: consider explicitly using function result
 
-error: non-binding let on an expression with `#[must_use]` type
+error: non-binding `let` on an expression with `#[must_use]` type
   --> $DIR/let_underscore_must_use.rs:83:5
    |
 LL |     let _ = if true { Ok(()) } else { Err(()) };
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = help: consider explicitly using expression value
 
-error: non-binding let on a result of a `#[must_use]` function
+error: non-binding `let` on a result of a `#[must_use]` function
   --> $DIR/let_underscore_must_use.rs:87:5
    |
 LL |     let _ = a.is_ok();
    |     ^^^^^^^^^^^^^^^^^^
    |
    = help: consider explicitly using function result
 
-error: non-binding let on an expression with `#[must_use]` type
+error: non-binding `let` on an expression with `#[must_use]` type
   --> $DIR/let_underscore_must_use.rs:89:5
    |
 LL |     let _ = a.map(|_| ());
    |     ^^^^^^^^^^^^^^^^^^^^^^
    |
    = help: consider explicitly using expression value
 
-error: non-binding let on an expression with `#[must_use]` type
+error: non-binding `let` on an expression with `#[must_use]` type
   --> $DIR/let_underscore_must_use.rs:91:5
    |
 LL |     let _ = a;