Merge pull request #17221 from maxbeatty/docs-preprocessor

Update Preprocessor section of homepage

docs/index.html

@@ -55,8 +55,8 @@ title: Bootstrap · The world's most popular mobile-first and responsive f
 
     <div class="row">
       <div class="col-sm-4 m-b-lg">
-        <img src="assets/img/sass-less.png" alt="Sass support" class="img-responsive">
-        <h4>Preprocessors</h4>
+        <img src="assets/img/sass.png" alt="Sass support" class="img-responsive">
+        <h4>Preprocessor</h4>
         <p>Bootstrap ships with vanilla CSS, but its source code utilizes <a href="../css/#sass">Sass</a>, a popular CSS preprocessor. Quickly get started with precompiled CSS or build on the source.</p>
       </div>
       <div class="col-sm-4 m-b-lg">