[css-values] Fix typo: 'Q' vs. 'q' in table entry (#1718)

resolves #1697

Author: ewilligers

css-values-3/Overview.bs

@@ -1071,7 +1071,7 @@ Absolute lengths: the ''cm'', ''mm'', ''q'', ''in'', ''pt'', ''pc'', ''px'' unit
 		<tr><th><dfn id="mm">mm</dfn>
 		    <td>millimeters
 		    <td>1mm = 1/10th of 1cm
-		<tr><th><dfn id="q">Q</dfn>
+		<tr><th><dfn id="q">q</dfn>
 		    <td>quarter-millimeters
 		    <td>1q = 1/40th of 1cm
 		<tr><th><dfn id="in">in</dfn>

css-values/Overview.bs

@@ -1157,7 +1157,7 @@ Absolute lengths: the ''cm'', ''mm'', ''q'', ''in'', ''pt'', ''pc'', ''px'' unit
 		<tr><th><dfn id="mm">mm</dfn>
 		    <td>millimeters
 		    <td>1mm = 1/10th of 1cm
-		<tr><th><dfn id="q">Q</dfn>
+		<tr><th><dfn id="q">q</dfn>
 		    <td>quarter-millimeters
 		    <td>1q = 1/40th of 1cm
 		<tr><th><dfn id="in">in</dfn>