ci: intro-to-cpp: emphasize free copy of C++ book for team members

Mention more explicitly that the software team provides a free copy of
the C++ book so team members don't think they're required to buy their
own.

Author: calcmogul

ci/intro-to-cpp/index.html

@@ -23,8 +23,9 @@ <h2 id="Bootstrap">Bootstrap</h2>
     <p>Once the development environment is set up, one may begin learning C++.
     We use the textbook <i>Programming: Principles and Practice Using C++
     (2<sup>nd</sup> edition)</i> by Bjarne Stroustrup (ISBN:
-    978-0-321-99278-9). Either a copy will be provided by the software team or
-    a copy can be bought <a href=
+    978-0-321-99278-9), and we provide a free electronic copy to all team
+    members (ask the software mentor for it 😀). If you prefer a physical copy
+    instead, one can be bought <a href=
     "https://www.informit.com/store/programming-principles-and-practice-using-c-plus-plus-9780321992789">
     directly from the publisher</a>. The current textbook errata are <a href=
     "https://www.stroustrup.com/PPPslides/PPP2errata.html">here</a>.</p>