Replace boost::optional with std::optional (#4877)

src/controllers/hotkeys/HotkeyHelpers.cpp

@@ -3,9 +3,10 @@
 #include "controllers/hotkeys/ActionNames.hpp"
 #include "controllers/hotkeys/HotkeyCategory.hpp"
 
-#include <boost/optional/optional.hpp>
 #include <QStringList>
 
+#include <optional>
+
 namespace chatterino {
 
 std::vector<QString> parseHotkeyArguments(QString argumentString)
@@ -31,7 +32,7 @@ std::vector<QString> parseHotkeyArguments(QString argumentString)
     return arguments;
 }
 
-boost::optional<ActionDefinition> findHotkeyActionDefinition(
+std::optional<ActionDefinition> findHotkeyActionDefinition(
     HotkeyCategory category, const QString &action)
 {
     auto allActions = actionNames.find(category);