Backport getting-started typo fixes to 3.27

[claude]

Requested by Ole Herman · Slack thread

Backport to the 3.27 release branch of #3718 (merged on master).

This cherry-picks 5 typo fixes across 4 getting-started documentation files. No behavioral changes — text/markdown corrections only.

Before / After

• A broken markdown link rendered as literal text [here] (url) — now a working link [here](url).
• A misspelled word and a couple of ungrammatical / lowercase-start sentences read awkwardly — now corrected.

Per-file fixes

• general-installation/installation-enterprise-free.markdown: broken markdown link [here] ( → [here](.
• 03-adding-modules.markdown: maserfiles → masterfiles.
• general-installation/_index.markdown: adjusting its settings → adjusting their settings (x2).
• pre-installation-checklist/vi-quick-start-guide.markdown: sentence capitalization type "i" → Type "i" and exit vi → Exit vi.

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Generated by Claude Code

[claude]

Superseded by #3722 — recreated with git cherry-pick -x for backport provenance.