[css-forms-1] Remove ::track from layout rule

Author: lukewarlow

css-forms-1/Overview.bs

@@ -682,11 +682,10 @@ progress {
 
 ## Layout ## {#stylesheet-layout}
 ```css
-input:not([type=file], [type=range]),
+input:not([type=file]),
 textarea,
 button,
 ::file-selector-button,
-::track,
 select,
 meter,
 progress {
@@ -702,6 +701,7 @@ ISSUE: Refine meter, progress, switch and range input styling.
 ```css
 ::track {
   height: 1em;
+  background-color: transparent;
 }
 
 ::fill {