rustdoc: Correctly handle long crate names on mobile

Author: GuillaumeGomez

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

@@ -1937,12 +1937,15 @@ in src-script.js and main.js
 	.mobile-topbar h2 {
 		padding-bottom: 0;
 		margin: auto 0.5em auto auto;
-		overflow: hidden;
 		/* Rare exception to specifying font sizes in rem. Since the topbar
 		   height is specified in pixels, this also has to be specified in
 		   pixels to avoid overflowing the topbar when the user sets a bigger
 		   font size. */
 		font-size: 24px;
+		word-break: break-all;
+		/* In case the crate name is too long, we want users to be able to scroll the title. */
+		overflow: hidden auto;
+		max-height: 100%;
 	}
 
 	.mobile-topbar h2 a {