AK+Kernel: Unify Traits<T>::equals()'s argument order on different types

There was a small mishmash of argument order, as seen on the table:

                 | Traits<T>::equals(U, T) | Traits<T>::equals(T, U)
   ============= | ======================= | =======================
   uses equals() | HashMap                 | Vector, HashTable
defines equals() | *String[^1]             | ByteBuffer

[^1]: String, DeprecatedString, their Fly-type equivalents and KString.

This mostly meant that you couldn't use a StringView for finding a value
in Vector<String>.

I'm changing the order of arguments to make the trait type itself first
(`Traits<T>::equals(T, U)`), as I think it's more expected and makes us
more consistent with the rest of the functions that put the stored type
first (like StringUtils functions and binary_serach). I've also renamed
the variable name "other" in find functions to "entry" to give more
importance to the value.

With this change, each of the following lines will now compile
successfully:

    Vector<String>().contains_slow("WHF!"sv);
    HashTable<String>().contains("WHF!"sv);
    HashMap<ByteBuffer, int>().contains("WHF!"sv.bytes());

AK/Find.h

@@ -26,6 +26,7 @@ template<typename TEndIterator, IteratorPairWith<TEndIterator> TIterator, typena
 template<typename TEndIterator, IteratorPairWith<TEndIterator> TIterator, typename T>
 [[nodiscard]] constexpr TIterator find(TIterator first, TEndIterator last, T const& value)
 {
+    // FIXME: Use the iterator's trait type, and swap arguments in equals call.
     return find_if(first, last, [&](auto const& v) { return Traits<T>::equals(value, v); });
 }
 
@@ -33,6 +34,7 @@ template<typename TEndIterator, IteratorPairWith<TEndIterator> TIterator, typena
 [[nodiscard]] constexpr size_t find_index(TIterator first, TEndIterator last, T const& value)
 requires(requires(TIterator it) { it.index(); })
 {
+    // FIXME: Use the iterator's trait type, and swap arguments in equals call.
     return find_if(first, last, [&](auto const& v) { return Traits<T>::equals(value, v); }).index();
 }