Add dev-htmltools make target for docs

Author: wch

docs/Makefile

@@ -39,6 +39,9 @@ $(PYBIN): $(VENV)
 help:
 	@python -c "$$PRINT_HELP_PYSCRIPT" < $(MAKEFILE_LIST)
 
+dev-htmltools: $(PYBIN)  ## Install development version of htmltools
+	$(PYBIN)/pip install https://github.com/rstudio/py-htmltools/tarball/main
+
 deps: $(PYBIN)  ## Install build dependencies
 	$(PYBIN)/pip install pip --upgrade
 	$(PYBIN)/pip install -e ..[doc]

docs/README.md

@@ -8,6 +8,9 @@ This directory contains files to generate Shiny for Python API documentation, us
 To build the docs, first install the Python dependencies and Quarto extensions:
 
 ```bash
+# Install development version of htmltools (do this if you are using a development version of shiny)
+make dev-htmltools
+
 # Install build dependencies
 make deps
 ```