Small fixes in build instructions, fix warnings

Since the build instructions suggest using pipenv, we should
consistently use pipenv to install the packages.

Also remove some warnings about unavailable static files.

Fix a Sphinx deprecation warning.

Author: ngzhian

document/README.md

@@ -42,7 +42,7 @@ pipenv shell
 Install Python dependencies:
 
 ```
-pip install Sphinx==2.4.4
+pipenv install Sphinx==2.4.4
 ```
 
 ### Checking out the repository
@@ -80,7 +80,7 @@ To build the [single-page W3C version](https://webassembly.github.io/spec/core/b
 ```
 # cd back to root of git directory
 git clone https://github.com/tabatkins/bikeshed.git
-pip install --editable bikeshed
+pipenv install -e bikeshed
 bikeshed update
 ```
 

document/core/conf.py

@@ -186,7 +186,7 @@
 # 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,
 # so a file named "default.css" will overwrite the builtin "default.css".
-html_static_path = ['_static', 'static/custom.css']
+html_static_path = ['static/custom.css']
 
 # Add any extra paths that contain custom files (such as robots.txt or
 # .htaccess) here, relative to this directory. These files are copied

document/core/util/bikeshed/conf.py

@@ -130,7 +130,7 @@
 # a list of builtin themes.
 #
 html_theme = 'classic'
-html_add_permalinks = None
+html_add_permalinks = ''
 
 # Theme options are theme-specific and customize the look and feel of a theme
 # further.  For a list of options available for each theme, see the
@@ -176,7 +176,7 @@
 # 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,
 # so a file named "default.css" will overwrite the builtin "default.css".
-html_static_path = ['_static', 'static/custom.css']
+# html_static_path = ['_static', 'static/custom.css']
 
 # Add any extra paths that contain custom files (such as robots.txt or
 # .htaccess) here, relative to this directory. These files are copied

document/core/util/mathdef.py

@@ -1,5 +1,5 @@
 from sphinx.ext.mathbase import math
-from sphinx.ext.mathbase import MathDirective
+from sphinx.directives.patches import MathDirective
 from sphinx.util.texescape import tex_replace_map
 from sphinx.writers.html5 import HTML5Translator
 from sphinx.writers.latex import LaTeXTranslator

document/core/util/mathdefbs.py

@@ -4,7 +4,7 @@
 # mathdef.py controlled by buildername.
 
 from sphinx.ext.mathbase import math
-from sphinx.ext.mathbase import MathDirective
+from sphinx.directives.patches import MathDirective
 from sphinx.ext.mathjax import html_visit_math
 from sphinx.ext.mathjax import html_visit_displaymath
 from sphinx.writers.html5 import HTML5Translator