Simplify the name of the font-palette feature (#1044)

Including the at-rule doesn't help disambiguate, and for the most part
we only include the entry point to a feature, not the whole API surface.

features/font-palette.dist.yml

@@ -1,7 +1,7 @@
 # Generated from: font-palette.yml
 # Do not edit this file by hand. Edit the source file instead!
 
-name: font-palette and @font-palette-values
+name: font-palette
 description: The `font-palette` CSS property selects a color palette from the font, optionally overriding individual colors in the `@font-palette-values` at-rule.
 spec:
   - https://drafts.csswg.org/css-fonts-4/#font-palette-prop

features/font-palette.yml

@@ -1,4 +1,4 @@
-name: font-palette and @font-palette-values
+name: font-palette
 description: The `font-palette` CSS property selects a color palette from the font, optionally overriding individual colors in the `@font-palette-values` at-rule.
 spec:
   - https://drafts.csswg.org/css-fonts-4/#font-palette-prop