Fix toggle-click-deadspace rustdoc-gui test

Author: jsha

src/test/rustdoc-gui/toggle-click-deadspace.goml

@@ -1,6 +1,6 @@
 // This test ensures that clicking on a method summary, but not on the "[-]",
 // doesn't toggle the <details>.
-goto: file://|DOC_PATH|/test_docs/struct.Foo.html
+goto: file://|DOC_PATH|/lib2/struct.Foo.html
 assert-attribute: (".impl-items .rustdoc-toggle", {"open": ""})
 click: "h4.code-header" // This is the position of "pub" in "pub fn a_method"
 assert-attribute: (".impl-items .rustdoc-toggle", {"open": ""})