DOCS-9174: direct users to PHP.net for extension installation

Author: schmalliso

docs/tutorial/install-php-library.txt

@@ -7,19 +7,13 @@ Install the |php-library|
 Prerequisites
 -------------
 
-The MongoDB PHP Library is a high-level abstraction for the
-MongoDB PHP driver. As such, you must install the `mongodb`
-extension to use the |php-library|:
+The |php-library| is a high-level abstraction for the MongoDB PHP driver. As
+such, you must install the `mongodb` extension to use the library.
 
-.. code-block:: sh
-
-   pecl install mongodb
-   echo "extension=mongodb.so" >> `php --ini | grep "Loaded Configuration" | sed -e "s|.*:\s*||"`
-
-Instructions for installing the `mongodb` extension on HHVM may be
-found in the :php:`Installation with HHVM
-<mongodb.installation.hhvm>` article
-in the driver documentation.
+:php:`Installing the MongoDB PHP Driver <manual/en/mongodb.installation.php>`
+describes how to install the `mongodb` extension for PHP. Instructions for
+installing the driver for HHVM may be found in the :php:`Installation with HHVM
+<manual/en/mongodb.installation.hhvm>` article.
 
 Procedure
 ---------