Add a link to an index-able/crawl-able wiki mirroring service of the wiki

At the moment, the wiki is editable by GitHub users, so it is blocked from indexing. If you are searching for something related to this repo, Google and other search engines will not use the content for it.

This link hack just sticks a link on the README so search engines may prioritize it. At the moment, 0 pages from GitHub are index and only 7 pages from my proxy service are. If you add this, the rest should get indexed.

An indexable page looks like this: https://github-wiki-see.page/m/AUTOMATIC1111/stable-diffusion-webui/wiki/Command-Line-Arguments-and-Settings. It is not meant to be read, just indexed, and users are expected to click through to the GitHub copy.

https://github-wiki-see.page/ has more information about the situation. I built the tool and I'm happy to answer any questions I can.

Similar: https://github.com/MiSTer-devel/Main_MiSTer#main_mister-main-binary-and-wiki-repo:~:text=For%20the%20purposes%20of%20getting%20google%20to%20crawl%20the%20wiki%2C%20here%27s%20a%20link%20to%20the%20(not%20for%20humans)%20crawlable%20wiki

README.md

@@ -135,8 +135,11 @@ Find the instructions [here](https://github.com/AUTOMATIC1111/stable-diffusion-w
 Here's how to add code to this repo: [Contributing](https://github.com/AUTOMATIC1111/stable-diffusion-webui/wiki/Contributing)
 
 ## Documentation
+
 The documentation was moved from this README over to the project's [wiki](https://github.com/AUTOMATIC1111/stable-diffusion-webui/wiki).
 
+For the purposes of getting Google and other search engines to crawl the wiki, here's a link to the (not for humans) [crawlable wiki](https://github-wiki-see.page/m/AUTOMATIC1111/stable-diffusion-webui/wiki).
+
 ## Credits
 Licenses for borrowed code can be found in `Settings -> Licenses` screen, and also in `html/licenses.html` file.