Add section about LSP support by compiledb scons command

Adds a section explaining that a compilation database can be compiled
using scons to enable IDE features like autocomplete and more.

Author: paddy-exe

README.md

@@ -23,6 +23,14 @@ For getting started after cloning your own copy to your local machine, you shoul
 * change the `entry_symbol` string inside your `demo/bin/your-extension.gdextension` file to be configured for your GDExtension name. This should be the same as the `GDExtensionBool GDE_EXPORT` external C function. As the name suggests, this sets the entry function for your GDExtension to be loaded by the Godot editors C API.
 * register the classes you want Godot to interact with inside the `register_types.cpp` file in the initialization method (here `initialize_gdextension_types`) in the syntax `GDREGISTER_CLASS(CLASS-NAME);`.
 
+### Language Server Protocol (LSP) support
+Scons can generate a compilation database file named `compile_commands.json` which has information about every compiled unit in your project. This file enables IDEs to be able to offer features such as autocompletion and syntax highlighting for your GDExtension and godot-cpp classes. 
+
+To compile this file you can run this command in the project root directory:
+```shell
+scons compiledb=yes compile_commands.json
+``` 
+
 ## Usage - Actions
 
 This repository comes with a GitHub action that builds the GDExtension for cross-platform use. It triggers automatically for each pushed change. You can find and edit it in [builds.yml](.github/workflows/builds.yml).