Fix doc styling bug where underscores are invisible in some highlighted code....

chrome/common/extensions/docs/css/ApiRefStyles.css

 .todo, .comment { /* while we're working on doc, comment out display */
   color: rgb(255, 0, 0);
   display: none;
 }
 
 .tbd { /* style for comments that should be visible to all devs */
   color: rgb(125, 125, 125);
 }
 
 .pageData {
@@ skipping 70 matching lines @@
 }
 
 code {
   font-size:10pt
 }
 
 pre {
   font-size:9pt;
   background-color:#fafafa;
   border:1px solid #bbb;
-  line-height:125%;
   margin:1em 0 0 0;
   padding:.99em;
   overflow:auto;
   word-wrap:break-word
 }
 
 blockquote {
   text-align:justify;
   margin:1em 90px 0 70px;
   padding:0 20px
@@ skipping 1230 matching lines @@
   border-left:0px;
 }
 
 #codesiteContent.hideSideNav .g-tpl-170 .g-unit {
   display:block;
   margin:0 0 0 0px;
   width:auto;
   float:none
 }