Java: Adjust ClassInstanceExpr type argument predicates docs

The type arguments which these predicates have as result are for the
type of the created instance.

Previously the documentation said "provided to the constructor", which
is misleading / incorrect. Type arguments provided to the constructor
are specified directly after the `new` keyword:
```
class C {
    <T> C() {
    }
}

new <String> C();
```

And those are not part of the results of these predicates.

Author: Marcono1234

java/ql/lib/semmle/code/java/Expr.qll

@@ -1199,15 +1199,15 @@ class ClassInstanceExpr extends Expr, ConstructorCall, @classinstancexpr {
   }
 
   /**
-   * Gets a type argument provided to the constructor of this class instance creation expression.
+   * Gets a type argument of the type of the created instance.
    *
-   * This is used for instantiations of parameterized classes.
+   * This is used for instantiations of parameterized classes. For example for
+   * `new ArrayList<String>()` the result would be the expression representing `String`.
    */
   Expr getATypeArgument() { result = this.getTypeName().(TypeAccess).getATypeArgument() }
 
   /**
-   * Gets the type argument provided to the constructor of this class instance creation expression
-   * at the specified (zero-based) position.
+   * Gets the type argument of the type of the created instance, at the specified (zero-based) position.
    */
   Expr getTypeArgument(int index) {
     result = this.getTypeName().(TypeAccess).getTypeArgument(index)