Typo fixes, plus a couple of code changes....

common/extensions/docs/static/overview.html

Index: common/extensions/docs/static/overview.html
===================================================================
--- common/extensions/docs/static/overview.html	(revision 25878)
+++ common/extensions/docs/static/overview.html	(working copy)
@@ -79,7 +79,7 @@
 just as you would in an ordinary HTML page.
 Here's an example of referring to
 a file named <code>myimage.png</code>
-that's in a subdirectory named <code>images</code>.
+that's in a subfolder named <code>images</code>.
 </p>
 
 <pre>
@@ -101,7 +101,7 @@
 You can see the IDs for all your loaded extensions
 by going to the URL <b>chrome://extensions/</b>.
 The <em>&lt;pathToFile></em> is the location of the file
-under the extension's top directory;
+under the extension's top folder;
 it's the same as the relative URL.
 </p>