[css-tables] Clarified how cell 'height' works

This is probably stop-gap until I import the column-measure text and
adapt it for rows.

Author: FremyCompany

css-tables-3/Overview.bs

@@ -1968,12 +1968,13 @@ spec:css21; type:property; text:max-width
 			</div>
 
 			<p>
-				Since cells that were spanning more than one rows have not been sized correctly during row layout,
-				their height will need to be eventually distributed to the set of rows they spanned.
-				
-			<p>
+				Since during row layout the specified heights of cells in the row were ignored 
+					and cells that were spanning more than one rows have not been sized correctly,
+					their height will need to be eventually distributed to the set of rows they spanned.
 				This is done by running the same algorithm as the column measurement for spans N>1, 
-					with the span=1 value being initialized with the result of the previous row layout.
+					with the span=1 value being initialized with the largest of 
+					the resulting height of the previous row layout,
+					and the largest specified height of cells that span this row only.
 
 			<div class="issue">
 				Import the relevant section of [[#computing-column-measures]] here.