[css-fonts-4] Update syntax for font-stretch in font matching section

Fixes #3266

Author: litherum

css-fonts-4/Overview.bs

@@ -2919,7 +2919,7 @@ if all font style properties were set to their initial value.
 				are removed from the matching set. If there is no face
 				which contains the desired value, a stretch value is chosen using the rules below:
 
-				* If the desired stretch value is less than or equal to 100, stretch values below the
+				* If the desired stretch value is less than or equal to 100%, stretch values below the
 					desired stretch value are checked in descending order followed by
 					stretch values above the desired stretch value in ascending order until a
 					match is found.
@@ -2935,15 +2935,15 @@ if all font style properties were set to their initial value.
 				<div class="example" id="ascendingstretch">
 					This search algorithm can be thought of as a distance function, where the lowest-distance value present in the font family is selected, and all fonts not including that value are eliminated.
 
-					Consider a font family with three fonts, named A, B, and C, each with associated supported ranges for the 'font-stretch!!property' descriptor. If an element is styled with "font-stretch: 125", the search algorithm can be visualized as follows:
+					Consider a font family with three fonts, named A, B, and C, each with associated supported ranges for the 'font-stretch!!property' descriptor. If an element is styled with "font-stretch: 125%", the search algorithm can be visualized as follows:
 
 					<img src="images/stretchdistance.svg" alt="algorithm">
 
 					The font stretch ranges supported by fonts A, B, and C are shown in the graph above. As you can see, because font B contains the minimum stretch value across the entire family, font B would be selected by this algorithm. However, if font B were somehow eliminated from the family, font C would then contain the lowest distance in the family, so it would be selected.
 				</div>
 
 				<div class="example">
-					Similar to the <a href="#ascendingstretch">previous example</a>, here is the conceptual distance graph for an element styled with "font-stretch: 75":
+					Similar to the <a href="#ascendingstretch">previous example</a>, here is the conceptual distance graph for an element styled with "font-stretch: 75%":
 
 					<img src="images/stretchdistance2.svg" alt="distance graph">