Clarified deprecation message for this in describes

lib/jasmine-core/jasmine.js

@@ -4219,7 +4219,9 @@ getJasmineRequireObj().deprecatingSuiteProxy = function(j$) {
 /* eslint-disable compat/compat */
 // TODO: Remove this in the next major release.
 getJasmineRequireObj().deprecatingThisProxy = function(j$) {
-  var msg = "Access to 'this' in describe functions is deprecated.";
+  var msg =
+    "Access to 'this' in describe functions (and in arrow functions " +
+    'inside describe functions) is deprecated.';
 
   try {
     new Proxy({}, {});

spec/core/EnvSpec.js

@@ -768,7 +768,9 @@ describe('Env', function() {
 
   it("deprecates access to 'this' in describes", function() {
     jasmine.getEnv().requireProxy();
-    var msg = "Access to 'this' in describe functions is deprecated.",
+    var msg =
+        "Access to 'this' in describe functions (and in arrow " +
+        'functions inside describe functions) is deprecated.',
       ran = false;
     spyOn(env, 'deprecated');
 

src/core/deprecatingThisProxy.js

@@ -1,7 +1,9 @@
 /* eslint-disable compat/compat */
 // TODO: Remove this in the next major release.
 getJasmineRequireObj().deprecatingThisProxy = function(j$) {
-  var msg = "Access to 'this' in describe functions is deprecated.";
+  var msg =
+    "Access to 'this' in describe functions (and in arrow functions " +
+    'inside describe functions) is deprecated.';
 
   try {
     new Proxy({}, {});