adds clarifications

basics.html

@@ -170,6 +170,8 @@
             notes:
             - structure
             - who, when, why
+            - ability to inspect old versions
+            - ability to revert to old versions
           </section>
 
           <section id="motivation-playground" data-markdown>
@@ -832,7 +834,7 @@
             - breaking **master**
             - something takes longer
             - frequent interruptions
-            - comment out code
+            - (instead of) comment out code
 
             notes:
             - if logical commit without breaking do not branch