Modify error message for const (ASSIGNMENT_TO_CONST)

Closes #56953

GitOrigin-RevId: 5452a16
Change-Id: Icc1811b39a10cd0fe5b9155c52ef4f133cfc7f14
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/391489
Reviewed-by: Paul Berry <paulberry@google.com>
Reviewed-by: Brian Wilkerson <brianwilkerson@google.com>
Commit-Queue: Phil Quitslund <pquitslund@google.com>
Reviewed-by: Phil Quitslund <pquitslund@google.com>

pkg/analyzer/lib/src/error/codes.g.dart

@@ -156,7 +156,7 @@ class CompileTimeErrorCode extends ErrorCode {
   ///  No parameters.
   static const CompileTimeErrorCode ASSIGNMENT_TO_CONST = CompileTimeErrorCode(
     'ASSIGNMENT_TO_CONST',
-    "Constant variables can't be assigned a value.",
+    "Constant variables can't be assigned a value after initialization.",
     correctionMessage:
         "Try removing the assignment, or remove the modifier 'const' from the "
         "variable.",

pkg/analyzer/messages.yaml

@@ -788,7 +788,7 @@ CompileTimeErrorCode:
       }
       ```
   ASSIGNMENT_TO_CONST:
-    problemMessage: "Constant variables can't be assigned a value."
+    problemMessage: "Constant variables can't be assigned a value after initialization."
     correctionMessage: "Try removing the assignment, or remove the modifier 'const' from the variable."
     hasPublishedDocs: true
     comment: No parameters.