This commit updates the location of the Image Directive guide link in the left navigation menu. Now the link is located under the Feature Preview section.
Also, this commit updates the Image Directive guides to add a highlighted message that the directive is in the developer preview mode.
PR Close#47466
As an ongoing effort to stabilize the NgOptimizedImage API before existing the Developer Preview, this commit renames the `rawSrc` attribute used for the NgOptimizedImage selector matching to `ngSrc`. The `rawSrcset` is also renamed to `ngSrcset` for consistency.
The motivation for this change is to align the attribute name better with other built-in directives, such as `ngFor`, `ngIf`, `ngClass`, `ngStyle`, etc.
Note: this is technically a breaking change, but since the NgOptimizedImage directive is in the Developer Preview mode, we land the change in a patch branch.
PR Close#47362