add 'environment variable' following ''preferred-text-scale''

Author: davidsgrogan

css-fonts-5/Overview.bs

@@ -92,7 +92,7 @@ The recognized keywords in the [=text-scale=]
 
 <dl>
 	<dt><dfn for="text-scale">legacy</dfn></dt>
-	<dd>''env()/preferred-text-scale'' returns the user's OS-level font factor on mobile,
+	<dd>The ''env()/preferred-text-scale'' environment variable returns the user's OS-level font factor on mobile,
 	but 1 on desktop.
 	The document's ''font-size/medium'' font size incorporates UA-level font preferences.
 	OS-level font preferences are ignored.
@@ -101,7 +101,7 @@ The recognized keywords in the [=text-scale=]
 	including an unrecognized content attribute keyword.
 	</dd>
 	<dt><dfn>scale</dfn></dt>
-	<dd>''env()/preferred-text-scale'' returns the user's OS-level font preferences.
+	<dd>The ''env()/preferred-text-scale'' environment variable returns the user's OS-level font preferences.
 	The document's ''font-size/medium'' font size incorporates both UA-level and OS-level font preferences.</dd>
 </dl>
 
@@ -113,21 +113,21 @@ the user agent must set the computed ''font-size/medium'' font size
 to 16px multiplied by
 the font scale factor
 the user has chosen from any settings <i>provided by the user agent</i>.
-The ''preferred-text-scale'' value must be 1 on desktop platforms.
+The ''preferred-text-scale'' environment variable value must be 1 on desktop platforms.
 On mobile:
 <ul>
 	<li>if the operating system provides a text scale setting AND
 	the UA hasn't already applied that factor to the ''font-size/medium'' font size,
-	''env()/preferred-text-scale'' returns the multiplier
+	the ''env()/preferred-text-scale'' environment variable returns the multiplier
 	that the user has chosen in the operating system's text scale setting.
 
 	Note: At the time of publishing, all combinations of
 	Android, iOS,
-	Gecko, WebKit, Blink
+	Firefox, Safari, Chrome
 	satisfy this first condition.
 
 	</li>
-	<li>Otherwise ''env()/preferred-text-scale'' returns 1.</li>
+	<li>Otherwise the ''env()/preferred-text-scale'' environment variable returns 1.</li>
 </ul>
 
 <h3 id="scale-keyword">The 'scale' keyword</h3>
@@ -139,7 +139,7 @@ When the value of the [=text-scale=] content attribute is
 <a for=text-scale>scale</a>
 computed ''font-size/medium'' font size must match the user's preferred paragraph text size as determined from a combination of OS and UA preferences.
 
-The ''env()/preferred-text-scale'' value must be a number that,
+The ''env()/preferred-text-scale'' environment variable must return a number that,
 when multiplied by 16px,
 provides a <<length>> that matches that of the ''font-size/medium'' font size.