Chain assignments more typically

Author: skef

Overview.bs

@@ -586,7 +586,7 @@ incremental font:
 # shaping_unit is an array where each item has a code point, associated list of
 # layout features, and the design space point that code point is being rendered with.
 def supported_spans(shaping_unit, ift_font):
-  current_start, current_end, current_subset_def = None
+  current_start = current_end = current_subset_def = None
   supported_spans = []
 
   i = 0
@@ -611,7 +611,7 @@ def supported_spans(shaping_unit, ift_font):
     else:
       i += 1
 
-    current_start, current_end, current_subset_def = None
+    current_start = current_end = current_subset_def = None
 
   return supported_spans
 
@@ -2488,4 +2488,4 @@ to be used by default in most shaper implementations. This list was assembled fr
 <pre class=include>
 <!-- Edit feature-registry.csv to update this table. -->
 path: feature-registry.html
-</pre>
+</pre>