fix(docs): repoint references to the relocated contributing guide (#749)

fix(docs): repoint references to the relocated contributing guide

The guide moved to .github/CONTRIBUTING.md; these references still
resolved
against the old root location and 404 from where they are written.
Rewritten
using the correct relative depth.

- `.github/CONTRIBUTING.md`: in-guide links withdrawn one level to the
root
- `SECURITY.adoc`: CONTRIBUTING.md -> .github/CONTRIBUTING.md

Author: hyperpolymath

.github/CONTRIBUTING.md

@@ -4,9 +4,9 @@ Thank you for your interest in AffineScript — a practical language for
 resource-safe systems, compiling to typed WebAssembly. This guide covers
 how to set up a working tree, file useful bugs, and submit changes.
 
-For the language itself, start from [`README.adoc`](README.adoc). For
+For the language itself, start from [`README.adoc`](../README.adoc). For
 project state, blockers, and next-actions, see
-[`.machine_readable/descriptiles/STATE.a2ml`](.machine_readable/descriptiles/STATE.a2ml).
+[`.machine_readable/descriptiles/STATE.a2ml`](../.machine_readable/descriptiles/STATE.a2ml).
 
 ’’’’’
 
@@ -84,7 +84,7 @@ template](.github/ISSUE_TEMPLATE/bug_report.md) and include:
 
 ### Suggesting Features
 
-**Before suggesting:** 1. Skim [`docs/ROADMAP.adoc`](docs/ROADMAP.adoc)
+**Before suggesting:** 1. Skim [`docs/ROADMAP.adoc`](../docs/ROADMAP.adoc)
 and `.machine_readable/descriptiles/STATE.a2ml`. 2. Search existing
 issues and discussions.
 
@@ -178,4 +178,4 @@ participating you agree to abide by it.
 
 By contributing you agree your contribution is licensed under the
 project’s dual licence (MIT OR AGPL-3.0-or-later), as recorded in
-[`LICENSE`](LICENSE) and per-file SPDX headers.
+[`LICENSE`](../LICENSE) and per-file SPDX headers.

SECURITY.adoc

@@ -410,7 +410,7 @@ When using \{\{PROJECT_NAME}}, we recommend:
 * https://github.com/%7B%7BOWNER%7D%7D/%7B%7BREPO%7D%7D/security/advisories[Security
 Advisories]
 * link:CHANGELOG.md[Changelog]
-* link:CONTRIBUTING.md[Contributing Guidelines]
+* link:.github/CONTRIBUTING.md[Contributing Guidelines]
 * https://cve.mitre.org/[CVE Database]
 * https://www.first.org/cvss/calculator/3.1[CVSS Calculator]