Revise wording on unnecessary wildcard warning

My concern with the previous wording is that:
- Beginners will be confused by "these are always open"
- Users advanced enough to understand what that actually means won't benefit from seeing it in this warning message!

crates/reporting/src/error/canonicalize.rs

@@ -1017,9 +1017,20 @@ pub fn can_problem<'b>(
         }
         Problem::UnnecessaryOutputWildcard { region } => {
             doc = alloc.stack([
-                alloc.reflow("I see you annotated a wildcard in a place where it's not needed:"),
+                alloc.concat([
+                    alloc.reflow("This type annotation has a wildcard type variable ("),
+                    alloc.keyword("*"),
+                    alloc.reflow(") that isn't needed."),
+                ]),
                 alloc.region(lines.convert_region(region)),
-                alloc.reflow("Tag unions that are constants, or the return values of functions, are always inferred to be open by default! You can remove this annotation safely."),
+                alloc.concat([
+                    alloc.reflow("Annotations for tag unions which are constants, or which are returned from functions, work the same way with or without a "),
+                    alloc.keyword("*"),
+                    alloc.reflow(" at the end. (The "),
+                    alloc.keyword("*"),
+                    alloc.reflow(" means something different when the tag union is an argument to a function, though!)"),
+                ]),
+                alloc.reflow("You can safely remove this to make the code more concise without changing what it means."),
             ]);
             title = "UNNECESSARY WILDCARD".to_string();
             severity = Severity::Warning;

crates/reporting/tests/test_reporting.rs

@@ -11772,14 +11772,19 @@ All branches in an `if` must have the same type!
     @r###"
     ── UNNECESSARY WILDCARD ────────────────────────────────── /code/proj/Main.roc ─
 
-    I see you annotated a wildcard in a place where it's not needed:
+    This type annotation has a wildcard type variable (`*`) that isn't
+    needed.
 
     4│      f : {} -> [A, B]*
                             ^
 
-    Tag unions that are constants, or the return values of functions, are
-    always inferred to be open by default! You can remove this annotation
-    safely.
+    Annotations for tag unions which are constants, or which are returned
+    from functions, work the same way with or without a `*` at the end. (The
+    `*` means something different when the tag union is an argument to a
+    function, though!)
+
+    You can safely remove this to make the code more concise without
+    changing what it means.
     "###
     );