Enhance Styles for Hugo Syntaxes and Binary Examples

[tajmone]

Improve the colour styles for syntax mock-ups:

• Hugo syntax definitions (see Enhance Hugo Syntax Definitions and Examples #41):
  • Use different colours for:
    • The various token indicating optionality ([]), alternatives (|) and omissions (...).
    • Comments.
  • Update Sass/CSS stylesheets:
    • Add new style classes, as required.
  • Track all syntax definitions that need to be fixed, and add them to this task list.
• Binary code representations of compiled Hugo examples:
  • Use different colours for:
    • Memory addresses.
    • Byte values.
    • Token representations.
    • String representations.
    • Vars and parameters representations.
  • Update Sass/CSS stylesheets:
    • Reuse the same colour scheme of syntax definitions (Base2Tone Lake), but combine colours differently (e.g. use the light scheme instead of the dark one).
  • Track all binary code examples that need to be fixed, and add them to this task list.
• Document new styles in CONVENTIONS.md.
• Update Changelog:
  • Mention that these styles updates are the reason why the new release bumps up the MINOR version (1.0.0 → 1.1.0).

Since all of the above are just literal blocks, and no syntax highlighter is involved, styles need to be applied manually.