Manual: Reorganize Chapters 2 and 3

[Omikhleia]

Chapter c02

• Corrected apostrophes from straight to curly.
• Reorganized content flow to enhance coherence
  • Previously, the sequence oscillated between topics.
    We had: Setting up an editor (not the first thing I'd would have put an accent on), typing a SILE document (but we can't do anything with it yet), installing SILE, back to the SILE document (repetitive) for running instructions.
  • Now, it follows a more logical order:
    1. Installing SILE (straight on topic, we want it installed!).
    2. Setting up an editor (ok, let's finish setting up things...)
    3. Typing a SILE document and executing it (yay! fun things all grouped)

Chapter c03

• Corrected apostrophes, quotes and some typos.
• Adopted a more formal tone (and avoid comparing with past versions)
• Rewrote most of the introductory section on input languages (with ideas from the Wiki, and also a bit of AI assistance in the rephrasing)
• Removed some redundant/repeated content
• Corrected sectioning levels which did not seem consistent

[alerque]

Thanks! There will be some merge conflicts with some edits I was working on for install instructions but I'll take care of those, the copy edits and organizational sanity are much more important than a little merge effort!