Rollup merge of rust-lang#70005 - GuillaumeGomez:code-block-signs, r=kinnison

[rustdoc] Improve visibility for code blocks warnings

It appeared that a lot of people didn't notice when a code block was meant to fail compilation or wasn't tested at all. The changes here make the colors less transparent and the icon bigger. So before it looked like this:

![old-light](https://user-images.githubusercontent.com/3050060/76687070-f1cdbb80-6620-11ea-9b73-0c787dc671f7.png)
![old-dark](https://user-images.githubusercontent.com/3050060/76687079-f4c8ac00-6620-11ea-90fb-e548329e01b4.png)

And now it looks like this:

![new-light](https://user-images.githubusercontent.com/3050060/76687092-fd20e700-6620-11ea-9ebb-2b6852f00899.png)
![new-dark](https://user-images.githubusercontent.com/3050060/76687091-fd20e700-6620-11ea-8fea-6854c8367b97.png)

cc @rust-lang/rustdoc
r? @kinnison

Author: Centril

src/librustdoc/html/static/rustdoc.css

@@ -1032,7 +1032,7 @@ h3 > .collapse-toggle, h4 > .collapse-toggle {
 
 .information {
 	position: absolute;
-	left: -20px;
+	left: -25px;
 	margin-top: 7px;
 	z-index: 1;
 }
@@ -1047,12 +1047,13 @@ h3 > .collapse-toggle, h4 > .collapse-toggle {
 	width: 120px;
 	display: none;
 	text-align: center;
-	padding: 5px 3px;
+	padding: 5px 3px 3px 3px;
 	border-radius: 6px;
 	margin-left: 5px;
 	top: -5px;
 	left: 105%;
 	z-index: 10;
+	font-size: 16px;
 }
 
 .tooltip:hover .tooltiptext {
@@ -1063,14 +1064,20 @@ h3 > .collapse-toggle, h4 > .collapse-toggle {
 	content: " ";
 	position: absolute;
 	top: 50%;
-	left: 11px;
+	left: 16px;
 	margin-top: -5px;
 	border-width: 5px;
 	border-style: solid;
 }
 
+.tooltip.compile_fail, .tooltip.ignore {
+	font-weight: bold;
+	font-size: 20px;
+}
+
 .tooltip .tooltiptext {
 	border: 1px solid;
+	font-weight: normal;
 }
 
 pre.rust {

src/librustdoc/html/static/themes/dark.css

@@ -254,7 +254,7 @@ a.test-arrow:hover{
 }
 
 pre.compile_fail {
-	border-left: 2px solid rgba(255,0,0,.6);
+	border-left: 2px solid rgba(255,0,0,.8);
 }
 
 pre.compile_fail:hover, .information:hover + pre.compile_fail {
@@ -270,7 +270,7 @@ pre.ignore:hover, .information:hover + pre.ignore {
 }
 
 .tooltip.compile_fail {
-	color: rgba(255,0,0,.6);
+	color: rgba(255,0,0,.8);
 }
 
 .information > .compile_fail:hover {
@@ -282,16 +282,17 @@ pre.ignore:hover, .information:hover + pre.ignore {
 }
 
 .information > .ignore:hover {
-	color: rgba(255,142,0,1);
+	color: #ff9200;
 }
 
 .search-failed a {
 	color: #0089ff;
 }
 
 .tooltip .tooltiptext {
-	background-color: black;
+	background-color: #000;
 	color: #fff;
+	border-color: #000;
 }
 
 .tooltip .tooltiptext::after {

src/librustdoc/html/static/themes/light.css

@@ -248,43 +248,43 @@ a.test-arrow:hover{
 }
 
 pre.compile_fail {
-	border-left: 2px solid rgba(255,0,0,.4);
+	border-left: 2px solid rgba(255,0,0,.5);
 }
 
 pre.compile_fail:hover, .information:hover + pre.compile_fail {
 	border-left: 2px solid #f00;
 }
 
 pre.ignore {
-	border-left: 2px solid rgba(255,142,0,.4);
+	border-left: 2px solid rgba(255,142,0,.6);
 }
 
 pre.ignore:hover, .information:hover + pre.ignore {
 	border-left: 2px solid #ff9200;
 }
 
 .tooltip.compile_fail {
-	color: rgba(255,0,0,.3);
+	color: rgba(255,0,0,.5);
 }
 
 .information > .compile_fail:hover {
 	color: #f00;
 }
 
 .tooltip.ignore {
-	color: rgba(255,142,0,.3);
+	color: rgba(255,142,0,.6);
 }
 
 .information > .ignore:hover {
-	color: rgba(255,142,0,1);
+	color: #ff9200;
 }
 
 .search-failed a {
 	color: #0089ff;
 }
 
 .tooltip .tooltiptext {
-	background-color: black;
+	background-color: #000;
 	color: #fff;
 }