Edits the by Tech Writer Agent following the F5 Technical Writing Sty…

[travisamartin]

PR description draft

Style edits: plm-installation.md and plm-upgrade.md

This PR applies style edits to both PLM docs to align them with the F5 Technical Writing Style Guide. No technical content was changed.

Product naming (f5-product-names)

Replaced all uses of the NIC abbreviation in body prose with the full product name NGINX Ingress Controller. Abbreviating NGINX product names isn't permitted. Shell commands, variable names (NIC_NAMESPACE, NIC_RELEASE, NIC_POD), and Helm release names (nic) were left unchanged because they are literal command syntax.

Second person and active voice (second-person, active-voice)

• "This guide installs / upgrades" → "Use this guide to install / upgrade" — the guide doesn't act; the reader does.
• "The k8s.nginx.org/v1 Policy manifest…does not need to be rewritten" → "You don't need to rewrite…"
• "When namespace is omitted, NGINX Ingress Controller defaults…" → "When you omit the namespace…"

Contractions and tense (contractions, tense)

• "does not" / "has not" / "is not" / "cannot" → "doesn't" / "hasn't" / "isn't" / "can't" throughout.
• "you will have" → "you'll have".

Word list (word-list)

• "substitute" → "replace"
• "PLM storage enabled" → "PLM storage turned on" (enable-disable)

Ambiguous pronouns (pronouns)

• "It deliberately excludes the App Protect CRDs" → "The bundle deliberately excludes…"
• "Both mechanisms operate independently" → "The two mechanisms operate independently"
• "It does this by adding the finalizer" added to resolve "PLM adopts every resource" → ambiguous follow-on sentence

Conditional sentences — condition first (conditional-sentences)

• "You'll pass all four values…when you run helm upgrade" → "When you run helm upgrade, pass all four values…"
• "Before you turn on PLM storage, migrate every such Ingress" — preceding sentence restructured so the condition leads.
• Troubleshooting bullets restructured so the condition or trigger appears before the action.

Semicolons (semicolons)

• `--reuse-values` preserves…; the `--set` flags overlay PLM storage on top split into two sentences.
• Credentials Secret list item split from semicolon join into two sentences.

Paragraph structure and instruction order (paragraph-structure, step-formatting)

• In plm-installation.md, the install section was restructured: "install with --skip-crds. Apply…first" was contradictory. Rewritten as: "you must apply the controller's own CRDs before running helm install", with the kubectl apply command following naturally.
• Extra blank line before a shell block removed.
• "Send a normal request to confirm the application responds." (period) → colon, so the shell block reads as the step continuation.

Headings (headings, step-numbers-in-headings)

• ## Section 1: Attach to a VirtualServer → ## Attach to a VirtualServer
• ## Section 2: Attach to an Ingress → ## Attach to an Ingress
• ## Create the NIC Policy → ## Create the Policy
• ### 1. Upgrade NIC to enable PLM → ### 1. Upgrade NGINX Ingress Controller with PLM storage (both sections)

The "Section N:" prefix and numbered subheadings act as step numbers in headings, which isn't permitted. The cross-reference prose was updated to use a short bulleted list of links to the renamed headings.

Line wrapping

Removed all manual mid-sentence line breaks in prose. Text now wraps at the editor margin instead of at an arbitrary column, making diffs easier to read.‌​​​‍‌​‌⁣​‍‍​⁣⁣‌‌​‍​‌‌‍‍‍‌‍‌​⁣‍⁣‌​‌‍‌‌⁣‌‍​⁣‌‌⁣⁣⁣⁣⁣⁣‍⁣‌‌​‍⁠

[travisamartin]

Do we need to specify the Helm version?