Clarify suggestion for E0013

src/test/ui/consts/const-fn-not-safe-for-const.stderr

@@ -4,17 +4,21 @@ error[E0015]: calls in constant functions are limited to constant functions, tup
 LL |     random()
    |     ^^^^^^^^
 
-error[E0013]: constant functions cannot refer to statics, use a constant instead
+error[E0013]: constant functions cannot refer to statics
   --> $DIR/const-fn-not-safe-for-const.rs:20:5
    |
 LL |     Y
    |     ^
+   |
+   = help: consider extracting the value of the `static` to a `const`, and referring to that
 
-error[E0013]: constant functions cannot refer to statics, use a constant instead
+error[E0013]: constant functions cannot refer to statics
   --> $DIR/const-fn-not-safe-for-const.rs:25:6
    |
 LL |     &Y
    |      ^
+   |
+   = help: consider extracting the value of the `static` to a `const`, and referring to that
 
 error: aborting due to 3 previous errors
 

src/test/ui/issues/issue-17718-const-bad-values.stderr

@@ -7,17 +7,21 @@ LL | const C1: &'static mut [usize] = &mut [];
    = note: for more information, see https://github.com/rust-lang/rust/issues/57349
    = help: add `#![feature(const_mut_refs)]` to the crate attributes to enable
 
-error[E0013]: constants cannot refer to statics, use a constant instead
+error[E0013]: constants cannot refer to statics
   --> $DIR/issue-17718-const-bad-values.rs:5:46
    |
 LL | const C2: &'static mut usize = unsafe { &mut S };
    |                                              ^
+   |
+   = help: consider extracting the value of the `static` to a `const`, and referring to that
 
-error[E0013]: constants cannot refer to statics, use a constant instead
+error[E0013]: constants cannot refer to statics
   --> $DIR/issue-17718-const-bad-values.rs:5:46
    |
 LL | const C2: &'static mut usize = unsafe { &mut S };
    |                                              ^
+   |
+   = help: consider extracting the value of the `static` to a `const`, and referring to that
 
 error[E0658]: references in constants may only refer to immutable values
   --> $DIR/issue-17718-const-bad-values.rs:5:41

src/test/ui/issues/issue-17718-references.stderr

@@ -1,20 +1,26 @@
-error[E0013]: constants cannot refer to statics, use a constant instead
+error[E0013]: constants cannot refer to statics
   --> $DIR/issue-17718-references.rs:9:29
    |
 LL | const T2: &'static usize = &S;
    |                             ^
+   |
+   = help: consider extracting the value of the `static` to a `const`, and referring to that
 
-error[E0013]: constants cannot refer to statics, use a constant instead
+error[E0013]: constants cannot refer to statics
   --> $DIR/issue-17718-references.rs:14:19
    |
 LL | const T6: usize = S;
    |                   ^
+   |
+   = help: consider extracting the value of the `static` to a `const`, and referring to that
 
-error[E0013]: constants cannot refer to statics, use a constant instead
+error[E0013]: constants cannot refer to statics
   --> $DIR/issue-17718-references.rs:19:33
    |
 LL | const T10: Struct = Struct { a: S };
    |                                 ^
+   |
+   = help: consider extracting the value of the `static` to a `const`, and referring to that
 
 error: aborting due to 3 previous errors
 

src/test/ui/issues/issue-18118-2.rs

@@ -1,7 +1,6 @@
 pub fn main() {
     const z: &'static isize = {
         static p: isize = 3;
-        &p
-        //~^ ERROR constants cannot refer to statics, use a constant instead
+        &p //~ ERROR constants cannot refer to statics
     };
 }

src/test/ui/issues/issue-18118-2.stderr

@@ -1,8 +1,10 @@
-error[E0013]: constants cannot refer to statics, use a constant instead
+error[E0013]: constants cannot refer to statics
   --> $DIR/issue-18118-2.rs:4:10
    |
 LL |         &p
    |          ^
+   |
+   = help: consider extracting the value of the `static` to a `const`, and referring to that
 
 error: aborting due to previous error
 

src/test/ui/issues/issue-52060.stderr

@@ -1,8 +1,10 @@
-error[E0013]: constants cannot refer to statics, use a constant instead
+error[E0013]: constants cannot refer to statics
   --> $DIR/issue-52060.rs:4:26
    |
 LL | static B: [u32; 1] = [0; A.len()];
    |                          ^
+   |
+   = help: consider extracting the value of the `static` to a `const`, and referring to that
 
 error[E0080]: evaluation of constant value failed
   --> $DIR/issue-52060.rs:4:26