chore(skills): remove empty feeds category (#16153)

skills/feeds/ only contained a category-marker DESCRIPTION.md with no
actual skills in it. Removing the directory and the 'feeds' -> 'Feeds'
display-label mapping in website/scripts/extract-skills.py (the only
other reference in the repo).

skills/feeds/DESCRIPTION.md

@@ -1,3 +0,0 @@
----
-description: Skills for monitoring, aggregating, and processing RSS feeds, blogs, and web content sources.
----

website/scripts/extract-skills.py

@@ -26,7 +26,6 @@ CATEGORY_LABELS = {
     "dogfood": "Dogfood",
     "domain": "Domain",
     "email": "Email",
-    "feeds": "Feeds",
     "gaming": "Gaming",
     "gifs": "GIFs",
     "github": "GitHub",