Add information on cloning a Git branch/tag directly (#4800)

Co-authored-by: Hugo Locurcio <[email protected]>

development/compiling/getting_source.rst

@@ -37,6 +37,15 @@ For any stable release, visit the `release page <https://github.com/godotengine/
 and click on the link for the release you want.
 You can then download and extract the source from the download link on the page.
 
+With ``git``, you can also clone a stable release by specifying its branch or tag
+after the ``--branch`` argument::
+
+    # Clone the continuously maintained stable branch (`3.x` as of writing).
+    git clone https://github.com/godotengine/godot.git --branch 3.x
+
+    # Clone the `3.2.3-stable` tag. This is a fixed revision that will never change.
+    git clone https://github.com/godotengine/godot.git --branch 3.2.3-stable
+
 There are also generally branches besides ``master`` for each major version.
 
 After downloading the Godot source code,