Fix UI issues with Rustdoc scrape-examples feature.

* Help file was being loaded from the wrong place.
* CSS selector in JS has a typo.
* Line numbers are overflowing, change to display: grid to fix.

Author: willcrichton

src/librustdoc/html/static/css/rustdoc.css

@@ -2015,7 +2015,9 @@ in storage.js
 }
 
 .scraped-example .code-wrapper .example-wrap {
-	flex: 1;
+	display: grid;
+	grid-template-columns: max-content auto;
+	width: 100%;
 	overflow-x: auto;
 	overflow-y: hidden;
 	margin-bottom: 0;

src/librustdoc/html/static/js/scrape-examples.js

@@ -57,7 +57,7 @@
                     });
                 });
 
-            example.querySelector("next")
+            example.querySelector(".next")
                 .addEventListener("click", () => {
                     onChangeLoc(() => {
                         locIndex = (locIndex + 1) % locs.length;

src/librustdoc/html/static_files.rs

@@ -130,4 +130,4 @@ static_files! {
     nanum_barun_gothic_license => "static/fonts/NanumBarunGothic-LICENSE.txt",
 }
 
-pub(crate) static SCRAPE_EXAMPLES_HELP_MD: &str = include_str!("static/js/scrape-examples.js");
+pub(crate) static SCRAPE_EXAMPLES_HELP_MD: &str = include_str!("static/scrape-examples-help.md");