Update PyThemis installation instructions

content/themis/languages/python/installation.md

@@ -80,9 +80,6 @@ you can manually build and install the latest version of Themis from source code
 
  2. Create a "wheel" package
 
-    <!-- FIXME: For some reason (missing install tools in venv?) the build fails when venv is activated,
-                resolve this or if that's not an issue, just remove this comment -->
-    Run this command outside of virtual environment:
     ```bash
     make pythemis_make_wheel
     ```
@@ -92,15 +89,16 @@ you can manually build and install the latest version of Themis from source code
     Result: src/wrappers/themis/python/dist/pythemis-0.14.0-py2.py3-none-any.whl
     ```
 
- 3. Install PyThemis in your virtual environment
+ 3. Install PyThemis into virtual environment
 
     Activate your virtual environment and run
     ```bash
-    pip install src/wrappers/themis/python/dist/pythemis-0.14.0-py2.py3-none-any.whl
+    make pythemis_install_wheel
     ```
 
-If the virtual environment already contained PyThemis,
-add `--force-reinstall` option to `pip install` to rewrite the previous version
+    Or run `pip install pythemis-...-none-any.whl` (the package file previously created).
+    If the virtual environment already contained PyThemis of the same version,
+    add `--force-reinstall` option to rewrite the previous package.
 
 <!-- DRAFT FOR OS PACKAGES FOR PROPER GLOBAL INSTALLATION
 To install PyThemis globally, you need to create a system package first:
@@ -122,8 +120,8 @@ For Debian/Ubuntu it's a `.deb` file, install with `sudo dpkg -i <filename>`.
 [PEP 668](https://peps.python.org/pep-0668/) changed the way Python packages are managed.
 It is now recommended to use `pip install` to only install packages into isolated virtual environments
 while installing things system-wide should be done using OS package manager (like `apt` or `rpm`).
-This means running `sudo make pythemis_install` is no longer recommended as it copies files
-into system-managed Python directory that is no longer maintained by `pip`.
+This means running `sudo make pythemis_old_install` is no longer recommended as it copies files
+into system-managed Python directory (like `/usr/lib/python3.X/site-packages`) that is no longer maintained by `pip`.
 Consider building a `.whl` and installing it into your venv instead.
 {{< /hint >}}
 
@@ -133,7 +131,7 @@ Consider building a `.whl` and installing it into your venv instead.
  2. Install PyThemis package from the source code:
 
     ```bash
-    make pythemis_install
+    sudo make pythemis_old_install
     ```
 
     The package will be installed globally into the system.
@@ -143,3 +141,8 @@ Consider building a `.whl` and installing it into your venv instead.
     ```bash
     make prepare_tests_all test_python
     ```
+
+To remove PyThemis after using `pythemis_old_install`, run
+```bash
+sudo pip uninstall --break-system-packages pythemis
+```