Various tweaks

src/test/ui/issue-30302.stderr

@@ -10,10 +10,10 @@ error: unreachable pattern
   --> $DIR/issue-30302.rs:25:9
    |
 23 |         Nil => true,
-   |         --- this pattern matches any value
+   |         --- matches any value
 24 | //~^ WARN pattern binding `Nil` is named the same as one of the variants of the type `Stack`
 25 |         _ => false
-   |         ^ this is an unreachable pattern
+   |         ^ unreachable pattern
    |
 note: lint level defined here
   --> $DIR/issue-30302.rs:14:9

src/test/ui/issue-31221.stderr

@@ -2,9 +2,9 @@ error: unreachable pattern
   --> $DIR/issue-31221.rs:28:9
    |
 27 |         Var3 => (),
-   |         ---- this pattern matches any value
+   |         ---- matches any value
 28 |         Var2 => (),
-   |         ^^^^ this is an unreachable pattern
+   |         ^^^^ unreachable pattern
    |
 note: lint level defined here
   --> $DIR/issue-31221.rs:14:9
@@ -16,19 +16,17 @@ error: unreachable pattern
   --> $DIR/issue-31221.rs:34:9
    |
 33 |         &Var3 => (),
-   |         ----- this pattern matches any value
+   |         ----- matches any value
 34 |         &Var2 => (),
-   |         ^^^^^ this is an unreachable pattern
-   |
+   |         ^^^^^ unreachable pattern
 
 error: unreachable pattern
   --> $DIR/issue-31221.rs:41:9
    |
 40 |         (c, d) => (),
-   |         ------ this pattern matches any value
+   |         ------ matches any value
 41 |         anything => ()
-   |         ^^^^^^^^ this is an unreachable pattern
-   |
+   |         ^^^^^^^^ unreachable pattern
 
 error: aborting due to 3 previous errors
 

src/test/ui/use-mod.rs

@@ -10,7 +10,7 @@
 
 use foo::bar::{
     self,
-//~^ ERROR `self` import can only appear once in the list
+//~^ ERROR `self` import can only appear once in an import list
     Bar,
     self
 //~^ ERROR the name `bar` is defined multiple times

src/test/ui/use-mod.stderr

@@ -1,20 +1,17 @@
-error[E0430]: `self` import can only appear once in the list
+error[E0430]: `self` import can only appear once in an import list
   --> $DIR/use-mod.rs:12:5
    |
 12 |     self,
-   |     ^^^^
-   |
-note: another `self` import appears here
-  --> $DIR/use-mod.rs:15:5
-   |
+   |     ^^^^ can only appear once in an import list
+...
 15 |     self
-   |     ^^^^
+   |     ---- another `self` import appears here
 
 error[E0431]: `self` import can only appear in an import list with a non-empty prefix
   --> $DIR/use-mod.rs:19:6
    |
 19 | use {self};
-   |      ^^^^
+   |      ^^^^ can only appear in an import list with a non-empty prefix
 
 error[E0252]: the name `bar` is defined multiple times
   --> $DIR/use-mod.rs:15:5