Update GUI test

tests/rustdoc-gui/docblock-big-code-mobile.goml

@@ -1,13 +1,15 @@
 // If we have a long `<code>`, we need to ensure that it'll be fully displayed on mobile, meaning
 // that it'll be on two lines.
+
 emulate: "iPhone 8" // it has the following size: (375, 667)
 go-to: "file://" + |DOC_PATH| + "/test_docs/long_code_block/index.html"
-// We now check that the block is on two lines:
 show-text: true // We need to enable text draw to be able to have the "real" size
+
+// We now check that the block is on two lines:
 // Little explanations for this test: if the text wasn't displayed on two lines, it would take
-// around 20px (which is the font size).
-assert-property: (".docblock p > code", {"offsetHeight": "44"})
+// around 24px (which is the font size).
+assert-size: (".docblock p > code", {"height": 48})
 
 // Same check, but where the long code block is also a link
 go-to: "file://" + |DOC_PATH| + "/test_docs/long_code_block_link/index.html"
-assert-property: (".docblock p > a > code", {"offsetHeight": "44"})
+assert-size: (".docblock p > a > code", {"height": 48})