docs: intro/agent: minor fixes
docs: intro/services: minor fixes
docs: intro/join: minor fixes
docs: intro/checks: minor fixes
docs: intro/kv: minor fixes
docs: compatibility: minor fixes
docs: internals/architecture: minor fixes
docs: internals/sessions: minor fixes
docs: internals/acl: minor fixes
docs: internals/security: minor fixes
docs: agent/basics: minor fixes
docs: agent/dns: minor fixes
docs: agent/checks: minor fixes
docs: agent/watches: minor fixes