Deprecation notice on opening of add-on manual (PHP 8.1.0)

[Zignature]

Description of the problem
When running on PHP 8.1 opening a manual (local readme.md file) of any add-on sparks a deprecation notice.

How To Reproduce
Steps to reproduce the behavior:

1. Go to the cp/addons page
2. Open a manual of any add-on. The manual has to be the local readme.md file. External manuals are not affected of course.

Error Message

Deprecated
urlencode(): Passing null to parameter #1 ($string) of type string is deprecated
ee/legacy/libraries/Cp.php, line 552

Severity: E_DEPRECATED

Environment Details:

• EE Version: 7.2.6
• PHP Version: 8.1.0
• MariaDB Version: 10.4.24
• Apache Version: 2.4.54
• Windows 11 Pro 22H2 build 22621.963

[Zignature]

I noticed the plugin documentation file (README.md) needs a capitalized name.
readme.md doesn't work and README.md does work.

Environment Details:

• EE Version: 7.2.5+
• PHP Version: 8.1.0
• MariaDB Version: 10.4.24
• Apache Version: 2.4.54
• Windows 11 Pro 22H2 build 22621.963

[intoeetive]

@Zignature yes, that is correct as per the docs. The casing is important when working with files in EE.
https://docs.expressionengine.com/latest/development/guidelines/in-app-documentation.html

[Zignature]

Guess I missed that part in the docs. I apologize.