Flatten marketing paths ahead of wiring up the websites

Drop the redundant documentation/marketing/ nesting inherited from the
plugin repos, so files sit at marketing/<plugin>/<page>.md. These paths
become raw URLs pasted into Elementor pages and ACF fields, so they are
much cheaper to change now than once sites reference them.

Fixes the four cross-plugin links for their new depth, and corrects the
README, which still pointed at the abandoned per-repo documentation/
folders instead of this repo.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

marketing/dotjuice-elementor-tools/widgets/keyword-linker.md

@@ -0,0 +1,15 @@
+# Keyword Linker
+
+Turn chosen keywords into links automatically, across every post and page — without editing content by hand.
+
+## The problem it solves
+
+Internal linking (and the occasional important external link) is one of those SEO and UX basics that's simple in theory but tedious in practice: every time you mention a term you want linked, you have to remember to add the link manually, in every post, every time.
+
+## How it helps
+
+Define a keyword once, tell it where to link, and Keyword Linker automatically turns every matching mention of that word across your site's content into a link — with control over how many times per page it should link, whether to bold the result, and whether the link opens in a new tab or carries a "nofollow" attribute.
+
+## The result
+
+Consistent internal (or external) linking across your whole site, maintained from one central list instead of hunting through old posts by hand.