Add favicon to tmt docs

.gitignore

@@ -13,6 +13,7 @@ docs/plugins/test-checks.rst
 docs/_build
 docs/spec
 docs/stories
+docs/_static/tmt-small.png
 
 # Python
 

docs/Makefile

@@ -4,8 +4,11 @@
 .DEFAULT_GOAL := help
 .PHONY: help generate-plugins plugins/*.rst generate-stories generate-template-filters generate-autodocs clean
 
+LOGO_SRC = https://raw.githubusercontent.com/teemtee/docs/main/logo/tmt-small.png
+LOGO_DST = _static/tmt-small.png
+
 clean:
-	rm -rf _build stories spec code/autodocs/*.rst code/template-filters.rst
+	rm -rf _build stories spec code/autodocs/*.rst code/template-filters.rst $(LOGO_DST)
 	find plugins -name "*.rst" ! -name index.rst | xargs rm -f
 
 ##
@@ -18,7 +21,12 @@ TEMPLATESDIR  = templates
 
 PLUGINS_TEMPLATE := $(TEMPLATESDIR)/plugins.rst.j2
 
-generate: spec stories generate-lint-checks generate-template-filters generate-plugins generate-stories generate-autodocs  ## Refresh all generated documentation sources
+generate: $(LOGO_DST) spec stories generate-lint-checks generate-template-filters generate-plugins generate-stories generate-autodocs  ## Refresh all generated documentation sources
+
+# We can ignore the error: later, during the build, if the logo is
+# missing, Sphinx will complain.
+$(LOGO_DST):
+	-curl -f $(LOGO_SRC) -o $(LOGO_DST)
 
 spec:
 	mkdir -p spec

docs/conf.py

@@ -16,7 +16,7 @@
 import subprocess
 import sys
 from pathlib import Path
-from typing import TYPE_CHECKING, Optional
+from typing import TYPE_CHECKING, Any, Optional
 
 if TYPE_CHECKING:
     from sphinx.application import Sphinx
@@ -222,7 +222,7 @@ def _load_theme(
 # The name of an image file (within the static path) to use as favicon of the
 # docs.  This file should be a Windows icon file (.ico) being 16x16 or 32x32
 # pixels large.
-# html_favicon = None
+html_favicon = '_static/tmt-small.png'
 
 # Add any paths that contain custom static files (such as style sheets) here,
 # relative to this directory. They are copied after the builtin static files,
@@ -313,12 +313,15 @@ def _load_theme(
     ]
 
 
-def generate_tmt_docs(app: Sphinx) -> None:
+def generate_tmt_docs(app: Sphinx, config: Any) -> None:
     """ Run `make generate` to populate the auto-generated sources """
 
     conf_dir = Path(app.confdir)
     subprocess.run(["make", "generate"], cwd=conf_dir)
 
 
 def setup(app: Sphinx) -> None:
-    app.connect("builder-inited", generate_tmt_docs)
+    # Generate sources after loading configuration. That should build
+    # everything, including the logo, before Sphinx starts checking
+    # whether all input files exist.
+    app.connect("config-inited", generate_tmt_docs)