[css-text-4] Only accept "none" as a standalone keyword for text-fit

Follow-up to #13616.

Author: cdoublev

css-text-4/Overview.bs

@@ -9746,7 +9746,7 @@ Text fitting: the 'text-fit' property</h3>
 
 	<pre class="propdef">
 	Name: text-fit
-	Value: [ none | grow | shrink ] [consistent | per-line | per-line-all]? <<percentage>>?
+	Value: none | [ grow | shrink ] [ consistent | per-line | per-line-all ]? <<percentage>>?
 	Initial: none
 	Applies to: <a>block containers</a>
 	Inherited: no
@@ -9784,7 +9784,6 @@ Text fitting: the 'text-fit' property</h3>
 		<dd>
 		    Specifies that all lines in the container are scaled with a single
 			scaling factor.
-			This keyword has no effect if ''text-fit/none'' is specified.
 			If none of ''text-fit/consistent'', ''text-fit/per-line'', or
 			''text-fit/per-line-all'' are specified, ''text-fit/consistent'' is
 			assumed.
@@ -9795,15 +9794,13 @@ Text fitting: the 'text-fit' property</h3>
 		    Specifies that each line is scaled with its own scaling factor.
 			However, the last line of the block and lines that end in a forced
 			break are not scaled.
-			This keyword has no effect if ''text-fit/none'' is specified.
 		</dd>
 
 		<dt><dfn>per-line-all</dfn>
 		<dd>
 		    Specifies that each line is scaled with its own scaling factor,
 			including the last line of the block and lines that end in a forced
 			break.
-			This keyword has no effect if ''text-fit/none'' is specified.
 		</dd>
 
 		<dt><dfn>&lt;percentage&gt;</dfn>