Auto merge of #18043 - hiikezoe:webkit-text-stroke-width, r=daisuke

Make -webkit-text-stroke-width animatable.

<!-- Please describe your changes on the following line: -->
https://bugzilla.mozilla.org/show_bug.cgi?id=1389452

---
<!-- 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

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

@@ -747,7 +747,7 @@ ${helpers.predefined_type("-webkit-text-stroke-width",
                           products="gecko",
                           flags="APPLIES_TO_FIRST_LETTER APPLIES_TO_FIRST_LINE APPLIES_TO_PLACEHOLDER",
                           spec="https://compat.spec.whatwg.org/#the-webkit-text-stroke-width",
-                          animation_value_type="none")}
+                          animation_value_type="discrete")}
 
 // CSS Ruby Layout Module Level 1
 // https://drafts.csswg.org/css-ruby/