css: Use :focus-visible instead of our custom data-keyboard-focus

https://developer.mozilla.org/en-US/docs/Web/CSS/:focus-visible

:focus-visible is basically the exact same functionality as the custom
data-keyboard-focus attribute that devtools maintains. This CL converts
all of our uses of data-keyboard-focus in CSS to use :focus-visible.

This has no intended behaviour change although it's possible there are
small differences in our implementation vs. the web platform one, so
this might cause some regression with focus styles for keyboard
interaction.

I tested a few of these manually to verify they still do the same thing.

The CSS linter was unhappy about the ordering of some rules due to
specificity-ordering checks, so there is some re-ordering too.

A follow-up CL will remove our implementation of data-keyboard-focus.

Change-Id: Ifc273f7d82e16ea07e24ed2d1faa6f794a12501d
Reviewed-on: https://chromium-review.googlesource.com/c/devtools/devtools-frontend/+/2352236
Commit-Queue: Peter Marshall <[email protected]>
Reviewed-by: Jack Franklin <[email protected]>
Reviewed-by: Kalon Hinds <[email protected]>
Reviewed-by: Jack Lynch <[email protected]>
Reviewed-by: Brandon Goddard <[email protected]>
diff --git a/front_end/sources/watchExpressionsSidebarPane.css b/front_end/sources/watchExpressionsSidebarPane.css
index a53f73a..4e8c64e 100644
--- a/front_end/sources/watchExpressionsSidebarPane.css
+++ b/front_end/sources/watchExpressionsSidebarPane.css
@@ -101,7 +101,7 @@
   background-color: #f0f0f0;
 }
 
-.watch-expression-header:focus[data-keyboard-focus="true"] {
+.watch-expression-header:focus-visible {
   background: var(--focus-bg-color);
 }