Update installation instructions (#655)

* Update installation instructions

* Small fix for 2.x branch & make instructions brief

* Style fix

docs/install.rst

@@ -5,38 +5,40 @@ Installation
 Stable (2.x)
 ============
 
-Using PIP
+From PyPI
 ---------
 
 .. code-block:: bash
 
     pip install -U aiogram
 
-Using AUR
----------
-
-*aiogram* 2.x is also available in Arch Linux Repository, so you can install this framework
-on any Arch-based distribution like Arch Linux, Antergos, Manjaro, etc.
-
-To do this, just use pacman to install the *python-aiogram* package:
+From Arch Linux Repository
+--------------------------
 
 .. code-block:: bash
 
-    $ pacman -S python-aiogram
+    pacman -S python-aiogram
 
 Development build (3.x)
 =======================
 
-From test PyPi index
+From PyPI
 -----------------------
 
 .. code-block:: bash
 
-    pip install -U --extra-index-url https://test.pypi.org/simple/ --pre aiogram
+    pip install -U --pre aiogram
 
 From GitHub
 -----------
 
 .. code-block:: bash
 
     pip install https://github.com/aiogram/aiogram/archive/refs/heads/dev-3.x.zip
+
+From AUR
+--------
+
+.. code-block:: bash
+
+    yay -S python-aiogram3