exclude mention about constant from error message 'a-constant-or-a-read-only-property' to be more specific.

Author: a-tarasyuk

src/compiler/checker.ts

@@ -9339,7 +9339,7 @@ namespace ts {
                     if (accessExpression) {
                         markPropertyAsReferenced(prop, accessExpression, /*isThisAccess*/ accessExpression.expression.kind === SyntaxKind.ThisKeyword);
                         if (isAssignmentTarget(accessExpression) && (isReferenceToReadonlyEntity(accessExpression, prop) || isReferenceThroughNamespaceImport(accessExpression))) {
-                            error(accessExpression.argumentExpression, Diagnostics.Cannot_assign_to_0_because_it_is_a_constant_or_a_read_only_property, symbolToString(prop));
+                            error(accessExpression.argumentExpression, Diagnostics.Cannot_assign_to_0_because_it_is_a_read_only_property, symbolToString(prop));
                             return missingType;
                         }
                         if (cacheSymbol) {
@@ -15895,7 +15895,7 @@ namespace ts {
                         error(node, Diagnostics.Cannot_assign_to_0_because_it_is_a_constant, symbolToString(symbol));
                     }
                     else {
-                        error(node, Diagnostics.Cannot_assign_to_0_because_it_is_a_constant_or_a_read_only_property, symbolToString(symbol));
+                        error(node, Diagnostics.Cannot_assign_to_0_because_it_is_a_read_only_property, symbolToString(symbol));
                     }
                     return errorType;
                 }
@@ -18468,7 +18468,7 @@ namespace ts {
                 checkPropertyAccessibility(node, left.kind === SyntaxKind.SuperKeyword, apparentType, prop);
                 if (assignmentKind) {
                     if (isReferenceToReadonlyEntity(<Expression>node, prop) || isReferenceThroughNamespaceImport(<Expression>node)) {
-                        error(right, Diagnostics.Cannot_assign_to_0_because_it_is_a_constant_or_a_read_only_property, idText(right));
+                        error(right, Diagnostics.Cannot_assign_to_0_because_it_is_a_read_only_property, idText(right));
                         return errorType;
                     }
                 }

src/compiler/diagnosticMessages.json

@@ -1944,7 +1944,7 @@
         "category": "Error",
         "code": 2539
     },
-    "Cannot assign to '{0}' because it is a constant or a read-only property.": {
+    "Cannot assign to '{0}' because it is a read-only property.": {
         "category": "Error",
         "code": 2540
     },