Auto merge of #17424 - KuoE0:expose-moz-context-properties-on-stylo, r=heycam

Expose -moz-context-properties on stylo

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Gecko already exposed `-moz-context-properties` behind pref `svg.context-properties.content.enabled`. I think we should do the same thing on stylo and make the reftests of `context-fill` and `context-stroke` pass.

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- [x] `./mach build -d` does not report any errors
- [x] `./mach test-tidy` does not report any errors
- [x] These changes fix [Bug 1370797](https://bugzilla.mozilla.org/show_bug.cgi?id=1370797)

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- [ ] There are tests for these changes OR
- [x] These changes do not require tests because the tests are in gecko.

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

@@ -268,7 +268,6 @@ ${helpers.predefined_type("marker-end", "UrlOrNone", "Either::Second(None_)",
                    animation_value_type="none"
                    products="gecko"
                    spec="Nonstandard (Internal-only)"
-                   internal="True"
                    allow_empty="True">
     use values::CustomIdent;
     use values::computed::ComputedValueAsSpecified;