docs: clarify that the virtualenv activation assume bash

docs/contributing.rst

@@ -28,7 +28,8 b' for more details.'
 Getting started
 ---------------
 
-To get started with Kallithea development::
+To get started with Kallithea development run the following commands in your
+bash shell::
 
         hg clone https://kallithea-scm.org/repos/kallithea
         cd kallithea

docs/installation.rst

@@ -49,7 +49,7 b' Installation from repository source'
 -----------------------------------
 
 To install Kallithea in a virtualenv using the stable branch of the development
-repository, follow the instructions below::
+repository, use the following commands in your bash shell::
 
         hg clone https://kallithea-scm.org/repos/kallithea -u stable
         cd kallithea
@@ -79,7 +79,8 b' An additional benefit of virtualenv is t'
     python3 -m venv /srv/kallithea/venv
 
 - Activate the virtualenv in your current shell session and make sure the
-  basic requirements are up-to-date by running::
+  basic requirements are up-to-date by running the following commands in your
+  bash shell::
 
     . /srv/kallithea/venv/bin/activate
     pip install --upgrade pip setuptools