docs: clarify that READMEs should not include input/output variable tables (#787)

The registry auto-generates input/output documentation from
`variables.tf` and `outputs.tf`, so including these tables in
module/template READMEs is redundant and prone to drift.

This adds two bullets to the **Code Style** section of `AGENTS.md`:

- Do not include input/output variable tables in READMEs
- Usage examples (e.g., `module "..." { }` blocks) are still encouraged

Created on behalf of @DevelopmentCats

---------

Co-authored-by: blink-so[bot] <211532188+blink-so[bot]@users.noreply.github.com>
Co-authored-by: DevCats <christofer@coder.com>

Author: 3 people

AGENTS.md

@@ -28,6 +28,8 @@ bun test main.test.ts                                 # Run single TS test (from
 - Use semantic versioning; bump version via script when modifying modules
 - Docker tests require Linux or Colima/OrbStack (not Docker Desktop)
 - Use `tf` (not `hcl`) for code blocks in README; use relative icon paths (e.g., `../../../../.icons/`)
+- **Do NOT include input/output variable tables in module or template READMEs.** The registry automatically generates these from the Terraform source (e.g., variable and output blocks in `main.tf`). Adding them to the README is redundant and creates maintenance drift.
+- Usage examples (e.g., a `module "..." { }` block) are encouraged, but not tables enumerating inputs/outputs.
 
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