Drop obsolete annotations syntax

compiler/testData/psi/annotation/at/validDeclarations.kt

@@ -1,19 +1,19 @@
-private @open [Ann1(1)] @Ann2("1") Ann3("2") class A(
+private @open @[Ann1(1)] @Ann2("1") Ann3("2") class A(
         @volatile(1) private val x: @AnnType("3") @open Int,
         @private var y: Int,
         @open z: Int
 ) {
-    @private [Ann3(2)] @Ann4("4") fun foo() {
+    @private @[Ann3(2)] @Ann4("4") fun foo() {
         @data class LocalClass
 
         print(1)
 
         @inline(option1, option2)
 
-        [inline2] private
+        @[inline2] private
         fun inlineLocal() {}
 
-        [Ann]
+        @[Ann]
         private
         @abstract
         @volatile var x = 1
@@ -22,7 +22,7 @@ private @open [Ann1(1)] @Ann2("1") Ann3("2") class A(
     }
 
     val x: Int
-        @inject [inline] private @open get() = 1
+        @inject @[inline] private @open get() = 1
 
     @open @ann init {}
 
@@ -35,7 +35,7 @@ private @open [Ann1(1)] @Ann2("1") Ann3("2") class A(
     @private
     constructor()
 
-    fun <@ann("") [ann] T : R> foo() {}
+    fun <@ann("") @[ann] T : R> foo() {}
 }
 @private val x = 1