Add where to borrowck_could_not_prove

Author: workingjubilee

compiler/rustc_error_messages/locales/en-US/borrowck.ftl

@@ -6,7 +6,7 @@ borrowck_higher_ranked_lifetime_error =
     higher-ranked lifetime error
 
 borrowck_could_not_prove =
-    could not prove `{$predicate}`
+    could not prove `where {$predicate}`
 
 borrowck_could_not_normalize =
     could not normalize `{$value}`

tests/ui/higher-rank-trait-bounds/issue-59311.stderr

@@ -4,15 +4,15 @@ error: higher-ranked lifetime error
 LL |     v.t(|| {});
    |     ^^^^^^^^^^
    |
-   = note: could not prove `[closure@$DIR/issue-59311.rs:17:9: 17:11] well-formed`
+   = note: could not prove `where [closure@$DIR/issue-59311.rs:17:9: 17:11] well-formed`
 
 error: higher-ranked lifetime error
   --> $DIR/issue-59311.rs:17:9
    |
 LL |     v.t(|| {});
    |         ^^^^^
    |
-   = note: could not prove `for<'a> &'a V: 'static`
+   = note: could not prove `where for<'a> &'a V: 'static`
 
 error: aborting due to 2 previous errors
 

tests/ui/lifetimes/re-empty-in-error.stderr

@@ -4,7 +4,7 @@ error: higher-ranked lifetime error
 LL |     foo(&10);
    |     ^^^^^^^^
    |
-   = note: could not prove `for<'b> &'b (): 'a`
+   = note: could not prove `where for<'b> &'b (): 'a`
 
 error: aborting due to previous error