Update README.md heading content

The heading about module installation in the README.md file has been modified. The new heading is more descriptive and improves guidance for the user on how to install the SQL module.

README.md

@@ -27,7 +27,7 @@ Converts SQL files, Web API URIs into injectable function objects.
 
     $ composer require ray/query-module
 
-### Module install (SQL)
+### How to Install the SQL Module
 
 ```php
 use Ray\Di\AbstractModule;