[css-scrollbars-1] Temporarily update <wpt title> attributes to fix bikeshed errors.

This removes any:
* markdown lists
* blank lines
from <wpt title=""> attributes to fix the entire CSSWG repository spec
build being broken since the bikeshed upgrade documented in:
https://lists.w3.org/Archives/Public/spec-prod/2025OctDec/0004.html

Author: dbaron

css-scrollbars-1/Overview.bs

@@ -110,18 +110,17 @@ Value Definitions</h3>
 
 	<wpt title="
 		This section has partial test coverage.
-
 		Missing:
-		* Tests checking that the property does anything
-		* Tests checking that the colors apply to the right parts
-		* Initial value">
+		X Tests checking that the property does anything
+		X Tests checking that the colors apply to the right parts
+		X Initial value">
 	</wpt>
 
 	<wpt title="The following tests have no basis in the spec:
 		they assume that making the thumb and the track transparent must make the whole scollbar invisible.
 		This is not necessarily true:
-		* the scrollbar may have other parts, such as scroll up/down/left/right buttons
-		* the spec does not require that the thumb / track are painted solid with the specified colors">
+		X the scrollbar may have other parts, such as scroll up/down/left/right buttons
+		X the spec does not require that the thumb / track are painted solid with the specified colors">
 
 		scrollbar-color-012.html
 		transparent-on-root.html
@@ -172,7 +171,7 @@ Value Definitions</h3>
 	<wpt title="The following test about viewport propagation is useful but insufficient;
 			the test will pass if the property has no effect at all.
 			Also missing:
-			* tests that check the interaction with css-contain, and in particular that that disables propagation">
+			X tests that check the interaction with css-contain, and in particular that that disables propagation">
 
 		viewport-scrollbar.html
 	</wpt>
@@ -366,11 +365,10 @@ Interaction with non-standard features</h3>
 
 	<wpt title="
 		This section has partial test coverage.
-
 		Missing:
-		* Test that thin does something different from auto in at least some cases
-		* Test that none does not affect scrollability
-		* Initial value">
+		X Test that thin does something different from auto in at least some cases
+		X Test that none does not affect scrollability
+		X Initial value">
 	</wpt>
 
 	<pre class="propdef">