Also list <form> in error message as possible culprit

src/core/__tests__/ReactInstanceHandles-test.js

@@ -147,10 +147,10 @@ describe('ReactInstanceHandles', function() {
         'Invariant Violation: findComponentRoot(..., .0.1:0:junk): ' +
         'Unable to find element. This probably means the DOM was ' +
         'unexpectedly mutated (e.g., by the browser), usually due to ' +
-        'forgetting a <tbody> when using tables, nesting <p> or <a> tags, ' +
-        'or using non-SVG elements in an <svg> parent. Try inspecting the ' +
-        'child nodes of the element with React ' +
-        'ID `.0`.'
+        'forgetting a <tbody> when using tables, nesting tags ' +
+        'like <form>, <p>, or <a>, or using non-SVG elements in an <svg> ' +
+        'parent. ' +
+        'Try inspecting the child nodes of the element with React ID `.0`.'
       );
     });
   });