Type Guard Documentation Is Incorrectly Labeled as Deprecated

Nobody has claimed this yet.

### 🔎 Search Terms

The only source of online information for the proper use of typescript type guards (value is someType, asserts value is someType) is [this page](https://www.typescriptlang.org/docs/handbook/advanced-types.html), which has a big DEPRECATED banner at the top. Please REMOVE THIS BANNER until this documentation has a replacement, then make the "Go To New Page" button link to the updated documentation, not some top level page where user needs to once again search for this new page that actually does not exist. THIS IS VALUABLE INFORMATION and it needs to be easier to find and trust, this is one of the most important features of typescript!


### 🕗 Version & Regression Information

This is not code, it's documentation and I can't figure out how else to submit this bug but none of the "code questions" fit here. This documentation page has been like this for at least 2 years. Please fix 🙏

### ⏯ Playground Link

https://www.typescriptlang.org/docs/handbook/advanced-types.html

### 💻 Code

```ts
https://www.typescriptlang.org/docs/handbook/advanced-types.html
```

### 🙁 Actual behavior

Valid and important typescript documentation has deprecation banner and link to new page that does not link to new page and there is no new page, so it's difficult to understand how to use type-guards to get that awesome control flow analysis-based type narrowing. Instead, it looks like typscript is removing the feature (please don't!)

### 🙂 Expected behavior

Valid and important typescript documentation does not have deprecation banner. OR it has deprecation banner but the link to new page actually goes to the new and updated page. Users can find out how to use type-guards and actually trust the information and can use it with confidence.

### Additional information about the issue

Please tell me how to properly submit this bug if this is not the correct location or approach, I don't know what else to do

Start with the Advanced Types documentation page at https://www.typescriptlang.org/docs/handbook/advanced-types.html and inspect its DEPRECATED banner and “Go To New Page” link. Done means the banner is removed until replacement documentation exists, or the link points directly to the updated type-guards documentation.

Written by the indexing model from the issue text.