refactor(Ex22): apply template method to Timer

Rename the virtual tick() override in PelicanTimer to doExpired()
and give the base Timer class a non-virtual tick() that checks for
expiration and dispatches to doExpired(). The exercise starting
point now matches SolutionEx22.

Co-authored-by: Qwen 3.8 27B <qwen3.8_27b-q3_k_xl@lmstudio.local>

cmat/Ex22/PelicanTimer.cpp

@@ -1,11 +1,9 @@
-
-
-#include "PelicanTimer.h"
-
-PelicanTimer::PelicanTimer(Pelican &target, TargetFunc targetFunc) : myTarget(target), myTargetFunc(targetFunc) {}
-
-void PelicanTimer::tick() {
-    if (isExpired()) {
-        (myTarget.*myTargetFunc)();
-    }
-}
+
+
+#include "PelicanTimer.h"
+
+PelicanTimer::PelicanTimer(Pelican &target, TargetFunc targetFunc) : myTarget(target), myTargetFunc(targetFunc) {}
+
+void PelicanTimer::doExpired() {
+    (myTarget.*myTargetFunc)();
+}