[css-fonts-4] font-variation-settings and font-feature-settings what should be returned for getComputedValue

#1959

Author: Litherum

css-fonts-3/Fonts.src.html

@@ -4174,7 +4174,7 @@ <h3 id="font-feature-settings-prop">Low-level font feature settings control: the
 </p>
 
 <p id="ffs-map">The computed value of font-feature-settings is a map,
-  so any duplicates in the specified value must not be preserved. </p>
+  so any duplicates in the specified value must not be preserved. If the same axis name appears more than once, the value associated with the last appearance supersedes any previous value for that axis.</p>
 
 <pre>
 font-feature-settings: "dlig" 1;       /* dlig=1 enable discretionary ligatures */

css-fonts-4/Overview.bs

@@ -3262,7 +3262,7 @@ are clamped to the closest value supported by the font.
 
 Values are allowed to be fractional or negative.
 
-If the same axis name appears more than once, the value associated with the last appearance supersedes any previous value for that axis.
+If the same axis name appears more than once, the value associated with the last appearance supersedes any previous value for that axis. This deduplication is observable by accessing the computed value of this property.
 
 Although specifically defined for OpenType / TrueType variations,
 variation axes for other modern font formats that support font variations