[css-color-4] Clarify wording around color-interpolation-method and host syntax, w3c#11760

Author: svgeesus

css-color-4/Overview.bs

@@ -4689,16 +4689,20 @@ Color Space for Interpolation</h3>
 		The sRGB color space, which is neither linear-light nor perceptually uniform, is the choice here,
 		even though it produces poorer results (overly dark or greyish mixes).
 
-
-
 	These features are collectively termed the <dfn export>host syntax</dfn>.
-	They are not used by this specification itself,
-	only exposed so that other specifications can use them;
+
+	To permit a host syntax to indicate the [=interpolation color space=],
+	this specification exports a 
+	<a href="#color-interpolation-method">color-interpolation-method</a> production.
+	It is not used by this specification itself,
+	only exposed so that other specifications can use it;
 	<span class="non-normative">see e.g. use in [[css-images-4#linear-gradients]].</span>
+	
 	The host syntax should define
-	what the default [=interpolation color space=]  should be for each case,
-	and optionally provide syntax for authors to override this default.
-	If such syntax is part of a property value, it should use a <<color-interpolation-method>> token,
+	what the <em>default</em> [=interpolation color space=]  should be for each case,
+	and preferably provide syntax for authors to override this default.
+	If such syntax is part of a property value, it should use the
+	<a href="#color-interpolation-method">color-interpolation-method</a> production,
 	defined below for easy reference from other specifications.
 	This ensures consistency across CSS,
 	and that further customizations on how color interpolation is performed