Dropped side-by-side layout on getting_started

This already didn't look great with only three options, and larger font
sizes made it more awkward.

Author: sgravrock

css/_scss/getting_started.scss

@@ -2,8 +2,8 @@
 @import 'constants';
 
 .option {
-  width: 45%;
-  margin-bottom: 20px;
+  width: 100%;
+  margin-bottom: 30px;
 
   h2 {
     font-size: 1.1rem;
@@ -18,7 +18,6 @@
 
   pre {
     @include light-code();
-    font-size: 14px; // make things fit
     padding: 10px;
     margin-bottom: 1rem;
   }

pages/getting_started.html

@@ -28,15 +28,11 @@ <h2>Jasmine for Node.js</h2>
   <div class="option">
     <h2>Jasmine for Browsers</h2>
     <p>Add Jasmine to your package.json</p>
-    <pre>npm install --save-dev \
-    jasmine-browser-runner \
-    jasmine-core</pre>
+    <pre>npm install --save-dev jasmine-browser-runner jasmine-core</pre>
     <p>Initialize Jasmine in your project</p>
     <pre>npx jasmine-browser-runner init</pre>
     <p>Set jasmine as your test script in your package.json</p>
-    <pre>"scripts": {
-    "test": "jasmine-browser-runner runSpecs"
-}</pre>
+    <pre>"scripts": {"test": "jasmine-browser-runner runSpecs"}</pre>
     <p>Run your tests</p>
     <pre>npm test</pre>
     <p>