Rollup merge of rust-lang#92440 - GuillaumeGomez:fix-mobile-toggles, r=jsha

Fix mobile toggles position

Before:

![Screenshot from 2021-12-29 18-53-33](https://user-images.githubusercontent.com/3050060/147764842-082f6fa2-b631-4c47-ba34-ced76fe8494f.png)

After:

![Screenshot from 2021-12-29 18-52-48](https://user-images.githubusercontent.com/3050060/147764853-13046330-2442-4fad-b26a-84c167711b54.png)

r? `@jsha`

Author: matthiaskrgr

src/ci/docker/host-x86_64/x86_64-gnu-tools/Dockerfile

@@ -72,7 +72,7 @@ ENV PATH="/node-v14.4.0-linux-x64/bin:${PATH}"
 # https://github.com/puppeteer/puppeteer/issues/375
 #
 # We also specify the version in case we need to update it to go around cache limitations.
-RUN npm install -g browser-ui-test@0.5.1 --unsafe-perm=true
+RUN npm install -g browser-ui-test@0.5.3 --unsafe-perm=true
 
 ENV RUST_CONFIGURE_ARGS \
   --build=x86_64-unknown-linux-gnu \

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

@@ -2007,6 +2007,16 @@ details.rustdoc-toggle[open] > summary.hideme::after {
 		max-width: 100vw;
 		width: 100vw;
 	}
+
+	/* Position of the "[-]" element. */
+	details.rustdoc-toggle:not(.top-doc) > summary {
+		margin-left: 10px;
+	}
+	.impl-items > details.rustdoc-toggle > summary:not(.hideme)::before,
+	#main-content > details.rustdoc-toggle:not(.top-doc) > summary::before,
+	#main-content > div > details.rustdoc-toggle > summary::before {
+		left: -11px;
+	}
 }
 
 @media print {

src/test/rustdoc-gui/toggle-docs-mobile.goml

@@ -9,6 +9,16 @@ assert-attribute: (".top-doc", {"open": ""})
 click: (3, 280)
 assert-attribute: (".top-doc", {"open": ""})
 
+// Assert the position of the toggle on the top doc block.
+assert-position: (".top-doc summary::before", {"x": 4})
+// Assert the position of the toggle on the impl block.
+assert-position: ("#implementations + details > summary::before", {"x": 4})
+// Assert the position of the toggle on a method.
+assert-position: (
+    "#trait-implementations-list .impl-items .method-toggle > summary::before",
+    {"x": 4},
+)
+
 // Now we do the same but with a little bigger width
 size: (600, 600)
 assert-attribute: (".top-doc", {"open": ""})