Merge pull request #594 from nature-of-code/notion-update-docs

Another attempt to add callout for quote source and removing italics

content/02_forces.html

@@ -668,7 +668,7 @@ <h3 id="gravitational-attraction">Gravitational Attraction</h3>
     <figcaption>Figure 2.7: An acceleration vector pointing toward the mouse position</figcaption>
   </figure>
 </div>
-<p>Remember in <a href="/vectors#algorithm-3-interactive-motion">Chapter 1</a>, when I created an object accelerating toward the mouse (see Figure 2.7)? As I showed then, a vector can be thought of as the difference between two points, so to calculate a vector pointing from the circle to the mouse, I subtracted one point from another:</p>
+<p>Remember in Chapter 1, when I created an object accelerating toward the mouse (see Figure 2.7)? As I showed then, a vector can be thought of as the difference between two points, so to calculate a vector pointing from the circle to the mouse, I subtracted one point from another:</p>
 <pre class="codesplit" data-code-language="javascript">let direction = p5.Vector.sub(mouse, position);</pre>
 <p>Now I can do the same thing to calculate <span data-type="equation">\hat{r}</span>. The direction of the attraction force that object 1 exerts on object 2 is equal to the following:</p>
 <pre class="codesplit" data-code-language="javascript">let direction = p5.Vector.sub(position1, position2);