mdscrub: decode character references, keep block boundaries, narrow the fence

parity/golden/mdscrub/breaks.md

@@ -1,5 +1,5 @@
-The address was set with explicit line breaks:Twelve Mill LaneThe
-Valleyand the county beyond.
+The address was set with explicit line breaks: Twelve Mill Lane The
+Valley and the county beyond.
 
 A second paragraph, where the break sits mid sentence — the mill stood at
-thenorthern end of the valley, where the fall was steepest.
+the northern end of the valley, where the fall was steepest.

parity/golden/mdscrub/breaks.rust.md

@@ -1,9 +0,0 @@
-The address was set with explicit line breaks:
-Twelve Mill Lane
-The
-Valley
-and the county beyond.
-
-A second paragraph, where the break sits mid sentence — the mill stood at
-the
-northern end of the valley, where the fall was steepest.