Inconsistent navigation links in documentation

[astrojuanlu]

Description

Our documentation has inconsistent navigation links. Sometimes we point to "/stable" sometimes to nothing.

Context

Also spotted by @noklam

kedro/docs/source/_templates/layout.html

Lines 14 to 15 in 1f2adf1

	<a href="https://docs.kedro.org/projects/kedro-viz/en/stable/">Kedro-Viz</a>
	<a href="https://docs.kedro.org/projects/kedro-datasets">Kedro-Datasets</a>

Notice that now we have this problem in 3 different repos, as per #3586.

Implementation

Update all links to point to "nothing", so remove the "/en/stable" or "/stable" part from the links.