Start watching more resources when using make dev

- Also watch the top-level `/src` directory
- Extend the list of considered filename extensions to Markdown, HTML,
  and Python

CHANGES.rst

@@ -6,6 +6,11 @@ Changes
 Unreleased
 ==========
 
+- Start watching more resources when using ``make dev``
+
+  - Also watch the top-level ``src`` directory
+  - Extend the list of considered filename extensions to Markdown and HTML
+
 
 2.1.0 - 2022/07/06
 ==================

common-build/rules.mk

@@ -50,7 +50,7 @@ PYTHON          = python3
 PIP             = $(PYTHON) -m pip
 SPHINXBUILD     = $(ENV_DIR)/bin/sphinx-build
 SPHINXAUTOBUILD = $(ENV_DIR)/bin/sphinx-autobuild
-AUTOBUILD_OPTS  = --re-ignore '^(?!.+\.rst$$)' --open-browser --delay 0
+AUTOBUILD_OPTS  = --watch $(TOP_DIR)/src --re-ignore '^(?!.+\.(?:rst|md|mmd|html|css|js|py|conf)$$)' --open-browser --delay 0
 BUILD_DIR       = $(LOCAL_DIR)/.build
 SPHINX_ARGS     = . $(BUILD_DIR)
 SPHINX_OPTS     = -W -n