Docs: fix broken links

Author: alrra

doc/TOC.md

@@ -13,7 +13,7 @@
 * [CSS](css.md) — A guide to the default CSS.
 * [JavaScript](js.md) — A guide to the default JavaScript.
 * [.htaccess](https://github.com/h5bp/server-configs/blob/master/apache/README.md)
- — All about the Apache web server config (also see our
+ — All about the Apache web server configs (also see our
  [alternative server configs](https://github.com/h5bp/server-configs)).
 * [crossdomain.xml](crossdomain.md) — An introduction to making use of
  crossdomain requests.

doc/html.md

@@ -38,8 +38,8 @@ spec](http://www.whatwg.org/specs/web-apps/current-work/complete/semantics.html#
 (4.2.5.5 Specifying the document's character encoding), add your charset
 declaration early (before any ASCII art ;) to avoid a potential
 [encoding-related security
-issue](http://code.google.com/p/doctype/wiki/ArticleUtf7) in IE. It should come
-in the first [1024
+issue](http://code.google.com/p/doctype-mirror/wiki/ArticleUtf7) in IE. It
+should come in the first [1024
 bytes](http://www.whatwg.org/specs/web-apps/current-work/multipage/semantics.html#charset).
 
 The charset should also come before the `<title>` tag, due to [potential XSS

doc/usage.md

@@ -63,7 +63,10 @@ get you started. [About the JavaScript](js.md).
 
 ### .htaccess
 
-The default web server config is for Apache. [About the .htaccess](htaccess.md).
+The default web server config is for Apache. For more information, please refer
+to the [`.htaccess`
+documentation](https://github.com/h5bp/server-configs/blob/master/apache/README.md)
+in the [server configs](https://github.com/h5bp/server-configs) project.
 
 Host your site on a server other than Apache? You're likely to find the
 corresponding configuration file in our [server configs