Move OnChange callback in Option ctors

Parameter 'f' is passed by value and only copied once. Moving it to
avoid unnecessary copies.

closes https://github.com/official-stockfish/Stockfish/pull/5014

No functional change

src/ucioption.cpp

@@ -68,7 +68,7 @@ Option::Option(const char* v, OnChange f) :
     type("string"),
     min(0),
     max(0),
-    on_change(f) {
+    on_change(std::move(f)) {
     defaultValue = currentValue = v;
 }
 
@@ -76,7 +76,7 @@ Option::Option(bool v, OnChange f) :
     type("check"),
     min(0),
     max(0),
-    on_change(f) {
+    on_change(std::move(f)) {
     defaultValue = currentValue = (v ? "true" : "false");
 }
 
@@ -84,13 +84,13 @@ Option::Option(OnChange f) :
     type("button"),
     min(0),
     max(0),
-    on_change(f) {}
+    on_change(std::move(f)) {}
 
 Option::Option(double v, int minv, int maxv, OnChange f) :
     type("spin"),
     min(minv),
     max(maxv),
-    on_change(f) {
+    on_change(std::move(f)) {
     defaultValue = currentValue = std::to_string(v);
 }
 
@@ -98,7 +98,7 @@ Option::Option(const char* v, const char* cur, OnChange f) :
     type("combo"),
     min(0),
     max(0),
-    on_change(f) {
+    on_change(std::move(f)) {
     defaultValue = v;
     currentValue = cur;
 }