refactor: use black-standard double quotes

The community has converged on double-quotes. Using single quotes is
like swimming upstream. Stop swimming upstream.

docs/conf.py

@@ -9,57 +9,57 @@
 from setuptools_scm import get_version
 
 extensions = [
-    'sphinx.ext.autodoc',
-    'sphinx.ext.autosummary',
-    'sphinx.ext.coverage',
-    'sphinx.ext.viewcode',
-    'sphinx.ext.intersphinx',
+    "sphinx.ext.autodoc",
+    "sphinx.ext.autosummary",
+    "sphinx.ext.coverage",
+    "sphinx.ext.viewcode",
+    "sphinx.ext.intersphinx",
 ]
 
-autodoc_member_order = 'bysource'
-templates_path = ['_templates']
-source_suffix = '.rst'
-master_doc = 'index'
-project = 'pyvcd'
-copyright = '2021, Western Digital Corporation'
-author = 'Peter Grayson and Steven Sprouse'
-version = get_version(root='..', relative_to=__file__)
+autodoc_member_order = "bysource"
+templates_path = ["_templates"]
+source_suffix = ".rst"
+master_doc = "index"
+project = "pyvcd"
+copyright = "2021, Western Digital Corporation"
+author = "Peter Grayson and Steven Sprouse"
+version = get_version(root="..", relative_to=__file__)
 # release = '0.0.1'
-language = 'en'
-exclude_patterns = ['_build']
-pygments_style = 'sphinx'
+language = "en"
+exclude_patterns = ["_build"]
+pygments_style = "sphinx"
 todo_include_todos = False
 
 # Options for HTML output
-html_theme = 'sphinx_rtd_theme'
+html_theme = "sphinx_rtd_theme"
 # html_static_path = ['_static']
-htmlhelp_basename = 'pyvcddoc'
+htmlhelp_basename = "pyvcddoc"
 
 # Options for LaTeX output
 
 latex_elements = {}
 latex_documents = [
     (
         master_doc,
-        'pyvcd.tex',
-        'pyvcd Documentation',
-        'Peter Grayson and Steven Sprouse',
-        'manual',
+        "pyvcd.tex",
+        "pyvcd Documentation",
+        "Peter Grayson and Steven Sprouse",
+        "manual",
     ),
 ]
 
 # Options for manual page output
-man_pages = [(master_doc, 'pyvcd', 'pyvcd Documentation', [author], 1)]
+man_pages = [(master_doc, "pyvcd", "pyvcd Documentation", [author], 1)]
 
 # Options for Texinfo output
 texinfo_documents = [
     (
         master_doc,
-        'pyvcd',
-        'pyvcd Documentation',
+        "pyvcd",
+        "pyvcd Documentation",
         author,
-        'pyvcd',
-        'One line description of project.',
-        'Miscellaneous',
+        "pyvcd",
+        "One line description of project.",
+        "Miscellaneous",
     ),
 ]

pyproject.toml

@@ -7,7 +7,6 @@ build-backend = "setuptools.build_meta"
 [tool.black]
 line-length = 88
 target-version = ["py37"]
-skip-string-normalization = true
 exclude = '''
 (
     ^\/\..*$