Merge pull request #6192 from kenjis/fix-docs-special-characters-in-paths

docs: add note about special characters in paths

Author: kenjis

user_guide_src/source/installation/installing_composer.rst

@@ -39,6 +39,10 @@ The command above will create a "project-root" folder.
 If you omit the "project-root" argument, the command will create an
 "appstarter" folder, which can be renamed as appropriate.
 
+.. note:: CodeIgniter autoloader does not allow special characters that are illegal in filenames on certain operating systems.
+    The symbols that can be used are ``/``, ``_``, ``.``, ``:``, ``\`` and space.
+    So if you install CodeIgniter under the folder that contains the special characters like ``(``, ``)``, etc., CodeIgniter won't work.
+
 If you don't need or want phpunit installed, and all of its composer
 dependencies, then add the ``--no-dev`` option to the end of the above
 command line. That will result in only the framework, and the three

user_guide_src/source/installation/installing_manual.rst

@@ -22,6 +22,10 @@ Installation
 Download the `latest version <https://github.com/CodeIgniter4/framework/releases/latest>`_,
 and extract it to become your project root.
 
+.. note:: CodeIgniter autoloader does not allow special characters that are illegal in filenames on certain operating systems.
+    The symbols that can be used are ``/``, ``_``, ``.``, ``:``, ``\`` and space.
+    So if you install CodeIgniter under the folder that contains the special characters like ``(``, ``)``, etc., CodeIgniter won't work.
+
 Setting Up
 ----------