DevTools: [CSS] report matched selectors for pseudoId matches

LayoutTests/inspector/elements/elements-panel-styles-expected.txt

 Tests that elements panel shows proper styles in the sidebar panel.
 
 Foo
 [expanded] 
 -webkit-font-smoothing: subpixel-antialiased;
     element.style - subpixel-antialiased 
 border-bottom-left-radius: 5px;
     .foo - 5px elements-panel-styles.css:21
 border-bottom-right-radius: 5px;
     .foo - 5px elements-panel-styles.css:21
@@ skipping 120 matching lines @@
 
 ======== Pseudo ::before element ========
 [expanded] 
 .foo::before  { (elements-panel-styles.css:57 -> elements-panel-styles.css:57:1)
 
 [expanded] 
 .foo::before  { (elements-panel-styles.css:40 -> elements-panel-styles.css:40:1)
 color: red;
 
 [expanded] 
-.foo, .foo::before  { (elements-panel-styles.css:34 -> elements-panel-styles.css:34:1)
+.foo, .foo::before  { (elements-panel-styles.css:34 -> elements-panel-styles.css:34:7)
 content: "[before Foo]";
 /-- overloaded --/ color: blue;
 display: block !important;
 
 
 ======== Pseudo ::after element ========
 [expanded] 
 .foo::after  { (elements-panel-styles.css:48 -> elements-panel-styles.css:48:1)
 font-family: courier;
 content: "[after Foo 2]";
 
 [expanded] 
 .foo::after  { (elements-panel-styles.css:44 -> elements-panel-styles.css:44:1)
 /-- overloaded --/ content: "[after Foo]";
 color: green;