Fixes readthedocs#5388 -- Added Documentation for constraint while using Conda

This patch adds few notes and warnings in the configuration file documentation,
which will warn the user if he/she is using conda enviroment to setup the docs.

Author: Parth1811

docs/config-file/v2.rst

@@ -90,7 +90,7 @@ Example:
 
 .. note::
 
-   PDF/epub/htmlzip output is not supported when using MkDocs  
+   PDF/epub/htmlzip output is not supported when using MkDocs
 
 python
 ~~~~~~
@@ -120,6 +120,11 @@ The Python version (this depends on :ref:`config-file/v2:build.image`).
 :Type: ``number``
 :Default: ``3``
 
+.. note::
+
+  If you are using a :ref:`Conda <config-file/v2:conda>` environment to manage
+  the build, this setting will not have any effect, as the Python version is managed by Conda.
+
 python.install
 ``````````````
 
@@ -150,6 +155,12 @@ Example:
          - requirements: docs/requirements.txt
          - requirements: requirements.txt
 
+.. warning::
+
+  If you are using a :ref:`Conda <config-file/v2:conda>` environment to
+  manage build, then this setting will not have any effect. Instead
+  add the extra requirements to `environment` file of Conda.
+
 Packages
 ''''''''
 
@@ -214,6 +225,13 @@ Read the Docs includes some libraries like scipy, numpy, etc.
 That you can access to them by enabling this option.
 See :ref:`builds:The build environment` for more details.
 
+.. warning::
+
+  If you are using a :ref:`Conda <config-file/v2:conda>` environment
+  to manage build, you should not set `system_packages` to `True`,
+  as this setting will not have any effect, since the virtual
+  environment creation is managed by Conda.
+
 conda
 ~~~~~