Explain linting suppressions (#5790)

* Reduce NOLINT

* Revert "Reduce NOLINT"

This reverts commit 96593d3.

* Explain NOLINT

We explicitly want to test copying the argument.

Author: rhaschke

tests/test_copy_move.cpp

@@ -193,11 +193,9 @@ TEST_SUBMODULE(copy_move_policies, m) {
 
     // test_move_and_copy_loads
     m.def("move_only", [](MoveOnlyInt m) { return m.value; });
-    // Changing this breaks the existing test: needs careful review.
-    // NOLINTNEXTLINE(performance-unnecessary-value-param)
+    // NOLINTNEXTLINE(performance-unnecessary-value-param): we want to test copying
     m.def("move_or_copy", [](MoveOrCopyInt m) { return m.value; });
-    // Changing this breaks the existing test: needs careful review.
-    // NOLINTNEXTLINE(performance-unnecessary-value-param)
+    // NOLINTNEXTLINE(performance-unnecessary-value-param): we want to test copying
     m.def("copy_only", [](CopyOnlyInt m) { return m.value; });
     m.def("move_pair",
           [](std::pair<MoveOnlyInt, MoveOrCopyInt> p) { return p.first.value + p.second.value; });