Update i8188 tests to the "using" syntax

Author: anatoliykmetyuk

tests/pos/i8188a.scala

@@ -1,7 +1,7 @@
 object Test {
   extension StrDeco on (tree: String) {
-    def show(given DummyImplicit): String = ???
-    def show(color: Boolean)(given DummyImplicit): String = ???
+    def show(using DummyImplicit): String = ???
+    def show(color: Boolean)(using DummyImplicit): String = ???
   }
 
   val a: String = "foo".show

tests/pos/i8188b.scala

@@ -1,6 +1,6 @@
 class Foo {
-  def f(x: String)(given DummyImplicit): String = x * 2
-  def f(x: String)(color: Boolean)(given DummyImplicit): String = x * 3
+  def f(x: String)(using DummyImplicit): String = x * 2
+  def f(x: String)(color: Boolean)(using DummyImplicit): String = x * 3
 }
 
 @main def Test = println(new Foo().f("foo"))

tests/pos/i8188c.scala

@@ -1,6 +1,6 @@
 class Foo {
-  def f(x: String)(given DummyImplicit): String = x * 2
-  def f(x: String)(given DummyImplicit)(color: Boolean): String = x * 3
+  def f(x: String)(using DummyImplicit): String = x * 2
+  def f(x: String)(using DummyImplicit)(color: Boolean): String = x * 3
 }
 
 @main def Test = println(new Foo().f("foo"))