width: Add quotes around .css() width argument (jquery#1118)

Fixes jquerygh-1102
Closes jquerygh-1118

Author: Matt Doyle

entries/width.xml

@@ -8,7 +8,7 @@
     </signature>
     <desc>Get the current computed width for the first element in the set of matched elements.</desc>
     <longdesc>
-      <p>The difference between <code>.css(width)</code> and <code>.width()</code> is that the latter returns a unit-less pixel value (for example, <code>400</code>) while the former returns a value with units intact (for example, <code>400px</code>). The <code>.width()</code> method is recommended when an element's width needs to be used in a mathematical calculation.</p>
+      <p>The difference between <code>.css( "width" )</code> and <code>.width()</code> is that the latter returns a unit-less pixel value (for example, <code>400</code>) while the former returns a value with units intact (for example, <code>400px</code>). The <code>.width()</code> method is recommended when an element's width needs to be used in a mathematical calculation.</p>
       <figure>
         <img src="/resources/0042_04_04.png"/>
         <figcaption>Figure 1 - Illustration of the measured width</figcaption>