Fix label not starting with lcase-letter

Co-authored-by: Fridtjof Stoldt <[email protected]>

Author: lukaslueg

clippy_lints/src/if_let_mutex.rs

@@ -64,7 +64,7 @@ impl<'tcx> LateLintPass<'tcx> for IfLetMutex {
                     let diag = |diag: &mut Diagnostic| {
                         diag.span_label(
                             op_mutex.span,
-                            "This Mutex will remain locked for the entire `if let`-block...",
+                            "this Mutex will remain locked for the entire `if let`-block...",
                         );
                         diag.span_label(
                             arm_mutex.span,

tests/ui/if_let_mutex.stderr

@@ -2,7 +2,7 @@ error: calling `Mutex::lock` inside the scope of another `Mutex::lock` causes a
   --> $DIR/if_let_mutex.rs:10:5
    |
 LL |       if let Err(locked) = m.lock() {
-   |       ^                    - This Mutex will remain locked for the entire `if let`-block...
+   |       ^                    - this Mutex will remain locked for the entire `if let`-block...
    |  _____|
    | |
 LL | |         do_stuff(locked);
@@ -20,7 +20,7 @@ error: calling `Mutex::lock` inside the scope of another `Mutex::lock` causes a
   --> $DIR/if_let_mutex.rs:22:5
    |
 LL |       if let Some(locked) = m.lock().unwrap().deref() {
-   |       ^                     - This Mutex will remain locked for the entire `if let`-block...
+   |       ^                     - this Mutex will remain locked for the entire `if let`-block...
    |  _____|
    | |
 LL | |         do_stuff(locked);
@@ -37,7 +37,7 @@ error: calling `Mutex::lock` inside the scope of another `Mutex::lock` causes a
   --> $DIR/if_let_mutex.rs:43:5
    |
 LL |       if let Ok(i) = mutex.lock() {
-   |       ^              ----- This Mutex will remain locked for the entire `if let`-block...
+   |       ^              ----- this Mutex will remain locked for the entire `if let`-block...
    |  _____|
    | |
 LL | |         do_stuff(i);