message: Fix sphinx docs build
  A literal backslash must be escaped, as \u is the escape sequence for
  unicode characters.
diff: @@ -150,7 +150,7 @@ latex_elements = {
  # Additional stuff for the LaTeX preamble.
  #
  - 'preamble': '\usepackage[strings]{underscore}',
  + 'preamble': '\\usepackage[strings]{underscore}',
  # Latex figure (float) alignment
  #
  