[text-auditor] Fix two clear grammar errors in user-facing runtime/CLI error messages

## Text Improvements

The following user-facing text issues were found in the repository. Each is a low-effort fix.

### 1. Runtime error message is grammatically incorrect (`failed write`)

**File:** `x-pack/osquerybeat/internal/osqd/osqueryd.go` (line 369)
**Current text:** `failed write osquery extension autoload file, %w`
**Suggested fix:** `failed to write osquery extension autoload file: %w`
**Why:** Clear grammar error in a returned runtime error message; adding `to` and using `:` follows existing Go error-message patterns in this codebase.

### 2. CLI error message is grammatically incorrect (`failed finding`)

**File:** `dev-tools/cmd/module_include_list/module_include_list.go` (line 237)
**Current text:** `failed finding modules and datasets: %w`
**Suggested fix:** `failed to find modules and datasets: %w`
**Why:** Clear grammar error in user-facing CLI error output.

## Suggested Actions

- [ ] Replace `failed write osquery extension autoload file, %w` with `failed to write osquery extension autoload file: %w` in `x-pack/osquerybeat/internal/osqd/osqueryd.go`.
- [ ] Replace `failed finding modules and datasets: %w` with `failed to find modules and datasets: %w` in `dev-tools/cmd/module_include_list/module_include_list.go`.

## Audit Notes

- Completeness pass for the exact patterns (`failed write osquery extension autoload file`, `failed finding modules and datasets`) found only the two occurrences above.
- Checked existing open `[text-auditor]` issues and `/tmp/previous-findings.json`; no existing issue tracks these exact strings.

---
[What is this?](https://ela.st/github-ai-tools) | [From workflow: Text Auditor](https://github.com/elastic/beats/actions/runs/27282241180)

Give us feedback! React with 🚀 if perfect, 👍 if helpful, 👎 if not.
> - [x] expires on Jun 17, 2026, 2:19 PM UTC