fix: Use short version of BROWSER command in django-ida Makefile

This matches the other Makefiles (and fixes the `docs` target)

Also, add docs target to .PHONY.

cookiecutter-django-ida/{{cookiecutter.repo_name}}/Makefile

@@ -1,6 +1,6 @@
 .DEFAULT_GOAL := help
 
-.PHONY: help clean requirements ci_requirements dev_requirements \
+.PHONY: help clean docs requirements ci_requirements dev_requirements \
         validation_requirements doc_requirements prod_requirements static shell \
         test coverage isort_check isort style lint quality pii_check validate \
         migrate html_coverage upgrade extract_translation dummy_translations \
@@ -9,17 +9,8 @@
         detect_changed_source_translations validate_translations check_keywords \
         install_transifex_client
 
-define BROWSER_PYSCRIPT
-import os, webbrowser, sys
-try:
-	from urllib import pathname2url
-except:
-	from urllib.request import pathname2url
-
-webbrowser.open("file://" + pathname2url(os.path.abspath(sys.argv[1])))
-endef
-export BROWSER_PYSCRIPT
-BROWSER := python -c "$$BROWSER_PYSCRIPT"
+# For opening files in a browser. Use like: $(BROWSER)relative/path/to/file.html
+BROWSER := python -m webbrowser file://$(CURDIR)/
 
 # Generates a help message. Borrowed from https://github.com/pydanny/cookiecutter-djangopackage.
 help: ## display this help message
@@ -68,7 +59,7 @@ test: clean ## run tests and generate coverage report
 # To be run from CI context
 coverage: clean
 	pytest --cov-report html
-	$(BROWSER) htmlcov/index.html
+	$(BROWSER)htmlcov/index.html
 
 isort_check: ## check that isort has been run
 	isort --check-only {{cookiecutter.project_name}}/