Improve documentation generation scripts and guide (#814)

* Improve documentation generation scripts

There is now a UNIX documentation generation script in the form of a
shell script. The Windows shell script has also been improved, and some
of the output of that script has been improved to match the UNIX one.

Because the scripts still use Lime to generate the documentation, the
shell script checks the kernel name using uname, and change the
documentation generation command ever so slightly. The reason for this
is that Lime only supports building to one platform at a time. This
makes manual intervention necessary, so the UNIX script checks for the
kernel ahead of time.

* Allow Linux-compatible kernels to work with UNIX doc generation script

Considering the variety of kernels available alongside ELF compatibility,
the UNIX documentation generation script has been modified to only check
for the Darwin kernel and assume every other kernel as Linux-compatible.

* Small consistency change in UNIX doc script when echoing pre-check message

* moving and small change

* cooler readme + docs generation guide

---------

Co-authored-by: ⍚~Nex <87421482+NexIsDumb@users.noreply.github.com>

Author: r6915ee

art/generateDoc.bat

@@ -1,6 +1,6 @@
-Here's the full guide on how to setup and compile Codename Engine!<br>
-
-> **Open the instructions for your platform**
+# Compiling Codename Engine
+Do you want to turn your source code into a playable build to play? Then you want to **compile the source code**, follow this guide.
+> **Open the instructions for your platform.**
 <details>
     <summary>Windows</summary>
 
@@ -38,3 +38,22 @@ Here's the full guide on how to setup and compile Codename Engine!<br>
 > You can also run `./cne-windows.bat -help` or `./cne-unix.sh -help` (depending on your platform) to check out more useful commands!<br>
 > For example `./cne-windows test` or `./cne-unix.sh test` builds the game and uses the source assets folder instead of the export one for easier development (although you can still use `lime test` normally).
 > - If you're running the terminal from the project's main folder, use instead `./building/cne-windows.bat -COMMAND HERE` or `./building/cne-unix.sh -COMMAND HERE` depending on your platform.
+
+# Generating Codename Engine's API documentation
+**Mainly recommended if you intend to fork the engine and make your own custom version to publish.**<br>Do you want to generate an API documentation so people can understand and mod your playable build? This documentation can be uploaded to your website.<br>If you just want to compile the engine normally for your hardcoded mod or for yourself you can skip this step.
+> **Select your platform to continue.**
+<details>
+    <summary>Windows</summary>
+
+1. Run `generate-docs-windows.bat` using cmd or double-clicking it and wait for the `doc.xml` to be generated inside the `docs` folder.
+</details>
+<details>
+    <summary>MacOS/Linux</summary>
+
+1. Run `generate-docs-unix.sh` using the terminal or double-clicking it and wait for the `doc.xml` to be generated inside the `docs` folder.
+</details>
+
+2. You can use this doc.xml file to generate a full HTML documentation (that you can open in your browser for example) using Haxe's [dox](https://github.com/HaxeFoundation/dox) generator; check [Codename Engine's webiste](https://github.com/CodenameCrew/codename-website/tree/main/api-generator) for example.
+
+> [!CAUTION]
+> The doc.xml might contain some sensible paths of your computer: make sure to filter the file before publishing it for everyone if you want to keep those paths private!<br>To filter and delete those paths, you may use Codename Engine's website's [doc filter Python script](https://github.com/CodenameCrew/codename-website/blob/main/api-generator/api/filter.py) by simply running it in the same folder of your `doc.xml` file. This script will also delete everything irrelevant to the engine that was generated in your documentation, such as libraries' (like OpenFL or Flixel) APIs.

building/README.md

@@ -0,0 +1,13 @@
+#!/usr/bin/env sh
+cd "$(dirname "$0")/.."
+echo "Generating documentation..."
+if [ $(uname) == "Darwin" ]; then
+    echo "Platform is macOS"
+    haxelib run lime build mac --haxeflag="-xml docs/doc.xml" -D doc-gen -D DOCUMENTATION --no-output
+else
+    echo "Platform is not macOS; assuming platform to be Linux compatible"
+    haxelib run lime build linux --haxeflag="-xml docs/doc.xml" -D doc-gen -D DOCUMENTATION --no-output
+fi
+
+echo "The XML file for the API documentation has been generated at docs/doc.xml."
+echo "For updating the API documentation hosted at the website, please replace codename-website/api-generator/api/doc.xml with the file listed above."

building/generate-docs-unix.sh

@@ -0,0 +1,8 @@
+@ECHO OFF
+cd /d "%~dp0.."
+echo Generating documentation...
+echo Platform is based on Windows
+haxelib run lime build windows --haxeflag="-xml docs/doc.xml" -D doc-gen -D DOCUMENTATION --no-output
+
+echo The XML file for the API documentation has been generated at docs/doc.xml.
+echo For updating the API documentation hosted at the website, please replace codename-website/api-generator/api/doc.xml with the file listed above.