Add GUI test for rustdoc search errors background

tests/rustdoc-gui/search-error.goml

@@ -0,0 +1,39 @@
+// Checks that the crate search filtering is handled correctly and changes the results.
+goto: "file://" + |DOC_PATH| + "/test_docs/index.html?search=sa'%3Bda'%3Bds"
+show-text: true
+
+define-function: (
+    "check-colors",
+    (theme, error_background),
+    block {
+        // Setting the theme.
+        local-storage: {"rustdoc-theme": |theme|, "rustdoc-use-system-theme": "false"}
+        // We reload the page so the local storage settings are being used.
+        reload:
+
+        wait-for: "#search .error code"
+        assert-css: ("#search .error code", {"background-color": |error_background|})
+    }
+)
+
+call-function: (
+    "check-colors",
+    {
+        "theme": "ayu",
+        "error_background": "rgb(79, 76, 76)",
+    },
+)
+call-function: (
+    "check-colors",
+    {
+        "theme": "dark",
+        "error_background": "rgb(72, 72, 72)",
+    },
+)
+call-function: (
+    "check-colors",
+    {
+        "theme": "light",
+        "error_background": "rgb(208, 204, 204)",
+    },
+)

tests/rustdoc-js-std/parser-errors.js

@@ -67,7 +67,7 @@ const PARSED = [
         returned: [],
         typeFilter: -1,
         userQuery: "a<\"p\">",
-        error: "`\"` cannot be used in generics",
+        error: "Unexpected `\"` in generics",
     },
     {
         elems: [],
@@ -373,7 +373,7 @@ const PARSED = [
         returned: [],
         typeFilter: -1,
         userQuery: "a!a",
-        error: '`!` can only be at the end of an ident',
+        error: 'Unexpected `!`: it can only be at the end of an ident',
     },
     {
         elems: [],