docs: fix section titles

Author: kenjis

user_guide_src/source/installation/installing_composer.rst

@@ -27,8 +27,8 @@ the latest released version of the framework.
 This installation technique would suit a developer who wishes to start
 a new CodeIgniter4 based project.
 
-Installation & Set Up
----------------------
+Installation
+------------
 
 In the folder above your project root::
 

user_guide_src/source/installation/running.rst

@@ -12,8 +12,8 @@ This section addresses how to use each technique, and explains some of the pros
 If you're new to CodeIgniter, please read the :doc:`Getting Started </intro/index>`
 section of the User Guide to begin learning how to build dynamic PHP applications. Enjoy!
 
-Initial Configuration & Set Up
-==============================
+Initial Configuration
+=====================
 
 #. Open the **app/Config/App.php** file with a text editor and
    set your base URL. If you need more flexibility, the baseURL may