improve diagnostics: break/continue wrong context

src/test/ui/issues/issue-28105.stderr

@@ -1,14 +1,14 @@
-error[E0268]: `continue` outside of loop
+error[E0268]: `continue` outside of a loop
   --> $DIR/issue-28105.rs:4:5
    |
 LL |     continue
-   |     ^^^^^^^^ cannot break outside of a loop
+   |     ^^^^^^^^ cannot `continue` outside of a loop
 
-error[E0268]: `break` outside of loop
+error[E0268]: `break` outside of a loop
   --> $DIR/issue-28105.rs:6:5
    |
 LL |     break
-   |     ^^^^^ cannot break outside of a loop
+   |     ^^^^^ cannot `break` outside of a loop
 
 error: aborting due to 2 previous errors
 

src/test/ui/issues/issue-43162.stderr

@@ -1,14 +1,14 @@
-error[E0268]: `break` outside of loop
+error[E0268]: `break` outside of a loop
   --> $DIR/issue-43162.rs:3:5
    |
 LL |     break true;
-   |     ^^^^^^^^^^ cannot break outside of a loop
+   |     ^^^^^^^^^^ cannot `break` outside of a loop
 
-error[E0268]: `break` outside of loop
+error[E0268]: `break` outside of a loop
   --> $DIR/issue-43162.rs:7:5
    |
 LL |     break {};
-   |     ^^^^^^^^ cannot break outside of a loop
+   |     ^^^^^^^^ cannot `break` outside of a loop
 
 error[E0308]: mismatched types
   --> $DIR/issue-43162.rs:1:13

src/test/ui/issues/issue-50576.stderr

@@ -4,17 +4,17 @@ error[E0426]: use of undeclared label `'L`
 LL |     |bool: [u8; break 'L]| 0;
    |                       ^^ undeclared label `'L`
 
-error[E0268]: `break` outside of loop
+error[E0268]: `break` outside of a loop
   --> $DIR/issue-50576.rs:2:17
    |
 LL |     |bool: [u8; break 'L]| 0;
-   |                 ^^^^^^^^ cannot break outside of a loop
+   |                 ^^^^^^^^ cannot `break` outside of a loop
 
-error[E0268]: `break` outside of loop
+error[E0268]: `break` outside of a loop
   --> $DIR/issue-50576.rs:5:16
    |
 LL |     Vec::<[u8; break]>::new();
-   |                ^^^^^ cannot break outside of a loop
+   |                ^^^^^ cannot `break` outside of a loop
 
 error: aborting due to 3 previous errors
 

src/test/ui/issues/issue-50581.stderr

@@ -1,8 +1,8 @@
-error[E0268]: `break` outside of loop
+error[E0268]: `break` outside of a loop
   --> $DIR/issue-50581.rs:2:14
    |
 LL |     |_: [u8; break]| ();
-   |              ^^^^^ cannot break outside of a loop
+   |              ^^^^^ cannot `break` outside of a loop
 
 error: aborting due to previous error