Rollup merge of #112133 - GuillaumeGomez:migrate-gui-test-color-10, r=notriddle

Migrate GUI colors test to original CSS color format

Follow-up of #111459.

r? `@notriddle`

Author: matthiaskrgr

tests/rustdoc-gui/theme-in-history.goml

@@ -7,21 +7,21 @@ set-local-storage: {
 }
 // We reload the page so the local storage settings are being used.
 reload:
-assert-css: ("body", { "background-color": "rgb(53, 53, 53)" })
+assert-css: ("body", { "background-color": "#353535" })
 assert-local-storage: { "rustdoc-theme": "dark" }
 
 // Now we go to the settings page.
 go-to: "file://" + |DOC_PATH| + "/settings.html"
 wait-for: "#settings"
 // We change the theme to "light".
 click: "#theme-light"
-wait-for-css: ("body", { "background-color": "rgb(255, 255, 255)" })
+wait-for-css: ("body", { "background-color": "white" })
 assert-local-storage: { "rustdoc-theme": "light" }
 
 // We go back in history.
 history-go-back:
 // Confirm that we're not on the settings page.
 assert-false: "#settings"
 // Check that the current theme is still "light".
-assert-css: ("body", { "background-color": "rgb(255, 255, 255)" })
+assert-css: ("body", { "background-color": "white" })
 assert-local-storage: { "rustdoc-theme": "light" }