Auto merge of #29810 - MendyBerger:master, r=Loirooriol

css `inset` should work on Layout 2020

<!-- Please describe your changes on the following line: -->
`top`, `bottom`, `left`, `right`, are already implemented in layout-2020, so adding the shorthand can be enabled.

---
<!-- Thank you for contributing to Servo! Please replace each `[ ]` by `[X]` when the step is complete, and replace `___` with appropriate data: -->
- [X] `./mach build -d` does not report any errors
- [X] `./mach test-tidy` does not report any errors
- [X] These changes fix #29705 (GitHub issue number if applicable)

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- [ ] There are tests for these changes OR
- [ ] These changes do not require tests because ___

I'm don't know if I need tests for this, how do I determine that?

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components/style/properties/shorthands/position.mako.rs

@@ -839,7 +839,7 @@ ${helpers.four_sides_shorthand(
     "inset",
     "%s",
     "specified::LengthPercentageOrAuto::parse",
-    engines="gecko servo-2013",
+    engines="gecko servo-2013 servo-2020",
     spec="https://drafts.csswg.org/css-logical/#propdef-inset",
     allow_quirks="No",
 )}
@@ -849,7 +849,7 @@ ${helpers.two_properties_shorthand(
     "inset-block-start",
     "inset-block-end",
     "specified::LengthPercentageOrAuto::parse",
-    engines="gecko servo-2013",
+    engines="gecko servo-2013 servo-2020",
     spec="https://drafts.csswg.org/css-logical/#propdef-inset-block"
 )}
 
@@ -858,6 +858,6 @@ ${helpers.two_properties_shorthand(
     "inset-inline-start",
     "inset-inline-end",
     "specified::LengthPercentageOrAuto::parse",
-    engines="gecko servo-2013",
+    engines="gecko servo-2013 servo-2020",
     spec="https://drafts.csswg.org/css-logical/#propdef-inset-inline"
 )}