Merge pull request #10962 from twbs/doc-h1-thru-h6-classes

document .h1 thru .h6; fixes part of #10102

css.html

@@ -587,7 +587,7 @@ base_url: "../"
 
     <!-- Headings -->
     <h2 id="type-headings">Headings</h2>
-    <p>All HTML headings, <code>&lt;h1&gt;</code> through <code>&lt;h6&gt;</code> are available.</p>
+    <p>All HTML headings, <code>&lt;h1&gt;</code> through <code>&lt;h6&gt;</code>, are available. <code>.h1</code> through <code>.h6</code> classes are also available, for when you want to match the font styling of a heading but still want your text to be displayed inline.</p>
     <div class="bs-example bs-example-type">
       <table class="table">
         <tbody>