fix(docs): prevent a virtual environment from failing a build

sphinx-build is passed a blanket "." to build all docs. However, if a
virtual environment is placed within the docs directory, sphinx will try
to build it which will fail due to some weird files it has.

This excludes the most common virtual environment directories from the
build to prevent this.

Signed-off-by: Boyan Karatotev <boyan.karatotev@arm.com>
Change-Id: Ieeb14cfc5730d21c986611feb0ed379c58dfcae2

.gitignore

@@ -43,3 +43,9 @@ tags
 
 # Node.js
 node_modules/
+
+# common python virtual environment directories
+.env/
+env/
+.venv/
+venv/

docs/conf.py

@@ -41,7 +41,8 @@ language = None
 # List of patterns, relative to source directory, that match files and
 # directories to ignore when looking for source files.
 # This pattern also affects html_static_path and html_extra_path .
-exclude_patterns = []
+# Don't try to build the venv in case it's placed with the sources
+exclude_patterns = [".env", "env", ".venv", "venv"]
 
 # The name of the Pygments (syntax highlighting) style to use.
 pygments_style = 'sphinx'