Merge bitcoin/bitcoin#24666: refactor: Fix coinselection.h include, Make COutput a struct

fab287cedd Clarify that COutput is a struct, not a class (MarcoFalke)
fa61cdf464 wallet: Fix coinselection include (MarcoFalke)

Pull request description:

  * Fix include (see commit message)
  * `{}`-init, see https://github.com/bitcoin/bitcoin/pull/24091#discussion_r831193284
  * `struct`, see https://github.com/bitcoin/bitcoin/pull/24091#discussion_r831192702

ACKs for top commit:
  theStack:
    Code-review ACK fab287cedd

Tree-SHA512: dd2cfb9c06a92295dbd8fbb6d56afcf00ebda2a0440e301d392cd183d1b9cd87626311d539e302a9e6c6521d69d6183c74a51934e3fc16e64a5dcaba60c7e3ce

src/qt/coincontroldialog.cpp

@@ -16,10 +16,11 @@
 #include <qt/platformstyle.h>
 #include <qt/walletmodel.h>
 
-#include <wallet/coincontrol.h>
 #include <interfaces/node.h>
 #include <key_io.h>
 #include <policy/policy.h>
+#include <wallet/coincontrol.h>
+#include <wallet/coinselection.h>
 #include <wallet/wallet.h>
 
 #include <QApplication>