Report syntax error on unescaped annotation

Also adjust parser testData

compiler/testData/psi/packages/PackageLeadingDotDoubleID.txt

@@ -10,6 +10,8 @@ JetFile: PackageLeadingDotDoubleID.kt
     <empty list>
   PsiWhiteSpace(' ')
   MODIFIER_LIST
+    PsiErrorElement:Use '@' symbol before annotations
+      <empty list>
     ANNOTATION_ENTRY
       CONSTRUCTOR_CALLEE
         TYPE_REFERENCE
@@ -17,4 +19,4 @@ JetFile: PackageLeadingDotDoubleID.kt
             REFERENCE_EXPRESSION
               PsiElement(IDENTIFIER)('b')
   PsiErrorElement:Expecting a top level declaration
-    <empty list>
+    <empty list>

compiler/testData/psi/packages/PackageLongNameDoubleID.txt

@@ -8,6 +8,8 @@ JetFile: PackageLongNameDoubleID.kt
     <empty list>
   PsiWhiteSpace(' ')
   MODIFIER_LIST
+    PsiErrorElement:Use '@' symbol before annotations
+      <empty list>
     ANNOTATION_ENTRY
       CONSTRUCTOR_CALLEE
         TYPE_REFERENCE
@@ -15,4 +17,4 @@ JetFile: PackageLongNameDoubleID.kt
             REFERENCE_EXPRESSION
               PsiElement(IDENTIFIER)('b')
   PsiErrorElement:Expecting a top level declaration
-    <empty list>
+    <empty list>