[NFC] Use appropriate names for `for_each` and `transform` template parameters

llvm/include/llvm/ADT/STLExtras.h

auto size(R &&Range,
                                             Range.begin())>::iterator_category,
                                         std::random_access_iterator_tag>::value,
                            void> * = nullptr) {
   return std::distance(Range.begin(), Range.end());
 }
 
 /// Provide wrappers to std::for_each which take ranges instead of having to
 /// pass begin/end explicitly.
-template <typename R, typename UnaryPredicate>
-UnaryPredicate for_each(R &&Range, UnaryPredicate P) {
-  return std::for_each(adl_begin(Range), adl_end(Range), P);
+template <typename R, typename UnaryFunction>
+UnaryFunction for_each(R &&Range, UnaryFunction F) {
+  return std::for_each(adl_begin(Range), adl_end(Range), F);
 }
 
 /// Provide wrappers to std::all_of which take ranges instead of having to pass
 /// begin/end explicitly.
 template <typename R, typename UnaryPredicate>
 bool all_of(R &&Range, UnaryPredicate P) {
   return std::all_of(adl_begin(Range), adl_end(Range), P);
 }

 /// element satisfying a given predicate occurs in a range.
 template <typename R, typename UnaryPredicate>
 auto count_if(R &&Range, UnaryPredicate P) {
   return std::count_if(adl_begin(Range), adl_end(Range), P);
 }
 
 /// Wrapper function around std::transform to apply a function to a range and
 /// store the result elsewhere.
-template <typename R, typename OutputIt, typename UnaryPredicate>
-OutputIt transform(R &&Range, OutputIt d_first, UnaryPredicate P) {
-  return std::transform(adl_begin(Range), adl_end(Range), d_first, P);
+template <typename R, typename OutputIt, typename UnaryFunction>
+OutputIt transform(R &&Range, OutputIt d_first, UnaryFunction F) {
+  return std::transform(adl_begin(Range), adl_end(Range), d_first, F);
 }
 
 /// Provide wrappers to std::partition which take ranges instead of having to
 /// pass begin/end explicitly.
 template <typename R, typename UnaryPredicate>
 auto partition(R &&Range, UnaryPredicate P) {
   return std::partition(adl_begin(Range), adl_end(Range), P);
 }