Auto merge of #19105 - mstange:move-fsbgcolor, r=emilio`

Bug 1414147 - Move fontSmoothingBackgroundColor from nsStyleUserInterface to nsFont, stylo changes.

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This will need to land in concert with [bug 1414147](https://bugzilla.mozilla.org/show_bug.cgi?id=1414147). Please don't r+ until the patch in that bug has been r+ed.

---
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- [X] `./mach build -d` does not report any errors
- [X] `./mach test-tidy` does not report any errors

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- [ ] There are tests for these changes OR
- [X] These changes do not require tests because they are required to make the Gecko build pass

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components/style/properties/longhand/font.mako.rs

@@ -2178,6 +2178,15 @@ ${helpers.single_keyword("-moz-osx-font-smoothing",
                          flags="APPLIES_TO_FIRST_LETTER APPLIES_TO_FIRST_LINE APPLIES_TO_PLACEHOLDER",
                          animation_value_type="discrete")}
 
+${helpers.predefined_type("-moz-font-smoothing-background-color",
+                          "RGBAColor",
+                          "RGBA::transparent()",
+                          animation_value_type="AnimatedRGBA",
+                          products="gecko",
+                          gecko_ffi_name="mFont.fontSmoothingBackgroundColor",
+                          internal=True,
+                          spec="None (Nonstandard internal property)")}
+
 ${helpers.predefined_type("-moz-min-font-size-ratio",
                           "Percentage",
                           "computed::Percentage::hundred()",

components/style/properties/longhand/pointing.mako.rs

@@ -181,14 +181,3 @@ ${helpers.predefined_type(
     ignored_when_colors_disabled=True,
     products="gecko",
 )}
-
-${helpers.predefined_type(
-    "-moz-font-smoothing-background-color",
-    "RGBAColor",
-    "RGBA::transparent()",
-    animation_value_type="AnimatedRGBA",
-    products="gecko",
-    gecko_ffi_name="mFontSmoothingBackgroundColor",
-    internal=True,
-    spec="None (Nonstandard internal property)"
-)}