Auto merge of #18206 - ferjm:bug1382369.grid.repeat.function, r=wafflespeanut

stylo: store specified value of grid layout repeat() function

- [X] `./mach build -d` does not report any errors
- [X] `./mach test-tidy` does not report any errors
- [X] These changes fix [Bug 1382369](https://bugzilla.mozilla.org/show_bug.cgi?id=1382369)

<!-- Reviewable:start -->
---
This change is [<img src="https://reviewable.io/review_button.svg" height="34" align="absmiddle" alt="Reviewable"/>](https://reviewable.io/reviews/servo/servo/18206)
<!-- Reviewable:end -->

components/style/properties/gecko.mako.rs

@@ -1895,7 +1895,7 @@ fn static_assert() {
         use nsstring::nsStringRepr;
         use values::CustomIdent;
         use values::generics::grid::{GridTemplateComponent, LineNameList, RepeatCount};
-        use values::generics::grid::{TrackList, TrackListType, TrackRepeat, TrackSize};
+        use values::generics::grid::{TrackList, TrackListType, TrackListValue, TrackRepeat, TrackSize};
 
         let value = match unsafe { ${self_grid}.mPtr.as_ref() } {
             None => return GridTemplateComponent::None,
@@ -1965,7 +1965,7 @@ fn static_assert() {
 
                     auto_repeat = Some(TrackRepeat{count, line_names, track_sizes});
                 } else {
-                    values.push(track_size);
+                    values.push(TrackListValue::TrackSize(track_size));
                 }
             }