Replace annotations with brackets in testData

Just in tests that changed after deprecation

compiler/testData/diagnostics/tests/suppress/oneWarning/onLocalVariable.kt

@@ -1,6 +1,6 @@
 class C {
     fun foo(): Any? {
-        [suppress("REDUNDANT_NULLABLE")]
+        @suppress("REDUNDANT_NULLABLE")
         val v: String?? = null <!USELESS_CAST!>as Nothing??<!>
         return v
     }