rustdoc: instead of .setting-name { width: 100% }, use default div CSS

src/librustdoc/html/static/css/settings.css

@@ -33,10 +33,6 @@
 	padding-bottom: 1px;
 }
 
-.radio-line .setting-name {
-	width: 100%;
-}
-
 .radio-line .choice {
 	margin-top: 0.1em;
 	margin-bottom: 0.1em;

src/librustdoc/html/static/js/settings.js

@@ -135,7 +135,7 @@
                 // This is a select setting.
                 output += `\
 <div class="radio-line" id="${js_data_name}">
-    <span class="setting-name">${setting_name}</span>
+    <div class="setting-name">${setting_name}</div>
 <div class="choices">`;
                 onEach(setting["options"], option => {
                     const checked = option === setting["default"] ? " checked" : "";