docs: fix 'allow to' grammar in text-to-image LoRA README

[mrchatam]

What does this PR do?

Tiny docs grammar fix in examples/text_to_image/README.md: "allow to control" → "allow controlling".

Validated against the surrounding LoRA advantages list.

Before submitting

• Did you use an AI agent (Claude Code, Codex, Cursor, etc.) to help with this PR? If so:
  • Did you read the Coding with AI agents guide?
  • Did you run a self-review on the diff?
  • Did you share the final self-review notes in the PR description or a comment?
• Did you read the contributor guideline?
• This PR fixes a typo / docs grammar issue.

Self-review notes

• Single-file docs-only change; confirmed the bullet still matches the LoRA scale-parameter meaning.
• No other allow to instances were mixed into this PR from other READMEs.

[github-actions]

Hi @mrchatam, thanks for the PR! It does not appear to link an issue it fixes. If this PR addresses an existing issue, please add a closing keyword (e.g. Fixes #1234) to the PR description so the issue is linked. See the contribution guide for more details. If this PR intentionally does not fix a tracked issue, a maintainer can add the no-issue-needed label to silence this reminder.

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