docs(style): clarify punctuation rules and edit scope - #74

Discussion Link

Link: No GitHub Discussion is linked. The change was requested in #33, with the semicolon and edit-scope refinements approved during implementation.

Context

The existing documentation rule only prohibits dashes as separators between concepts. It does not explicitly prohibit introducing the em-dash character elsewhere in generated Markdown. Additional guidance is needed to avoid semicolon-heavy prose without encouraging choppy sentences or unrelated edits to existing documents.

Closes #33

Solution

• Explicitly prohibit introducing Unicode U+2014 in newly written or rewritten Markdown and direct agents to rephrase sentences instead.
• Discourage semicolons in prose while preserving meaning and natural flow through conjunctions, clearer sentence structures, or separate sentences where appropriate. Preserve semicolons required by code, technical syntax, and verbatim quotations.
• Explicitly preserve existing text outside the requested scope and prohibit document scans or rewrites solely to remove existing punctuation.
• Align repository guidance, the documentation-style skill, both consumer templates, the published style reference, and the changelog's consumer adoption instructions.

Validation:

• markdownlint .github/instructions/documentation-style.instructions.md .github/plugins/devsquad/hooks/templates/.github/instructions/documentation-style.instructions.md .github/plugins/devsquad/skills/documentation-style/SKILL.md CHANGELOG.md: passed.
• bash .github/plugins/devsquad/hooks/sdd-init.sh verify: completed with valid JSON. Existing customized-file drift and four missing artifact-template targets were present before this change and remain unchanged.
• npm --prefix docs run build: passed, 39 pages built.
• git diff --check: passed before commit.
• Additional consistency checks confirmed identical rules across all five instruction/skill surfaces, preservation of their pre-existing text, and no literal em dashes or semicolons introduced in the new prose.

No repository-wide punctuation cleanup, enforcement hook, or version bump is included. Existing consumers can apply the scoped rules manually or preview managed-file updates before applying them.

Checklist

• Linked discussion exists
• Solution has been validated