[css-flexbox] Use Advisement class instead of Note class for flex longhand warnings.

Author: fantasai

css-flexbox/Overview.bs

@@ -1635,8 +1635,8 @@ Components of Flexibility</h3>
 	<p>
 		Individual components of flexibility can be controlled by independent longhand properties.
 
-	Note: Authors are encouraged to control flexibility using the 'flex' shorthand
-	rather than with component properties,
+	Advisement: Authors are encouraged to control flexibility using the 'flex' shorthand
+	rather than with its longhand properties directly,
 	as the shorthand correctly resets any unspecified components
 	to accommodate <a href="#flex-common">common uses</a>.
 
@@ -1654,8 +1654,8 @@ The 'flex-grow' property</h4>
 	Animatable: yes
 	</pre>
 
-	Note: Authors are encouraged to control flexibility using the 'flex' shorthand
-	rather than with component properties,
+	Advisement: Authors are encouraged to control flexibility using the 'flex' shorthand
+	rather than with 'flex-grow' directly,
 	as the shorthand correctly resets any unspecified components
 	to accommodate <a href="#flex-common">common uses</a>.
 
@@ -1678,8 +1678,8 @@ The 'flex-shrink' property</h4>
 	Animatable: yes
 	</pre>
 
-	Note: Authors are encouraged to control flexibility using the 'flex' shorthand
-	rather than with component properties,
+	Advisement: Authors are encouraged to control flexibility using the 'flex' shorthand
+	rather than with 'flex-shrink' directly,
 	as the shorthand correctly resets any unspecified components
 	to accommodate <a href="#flex-common">common uses</a>.
 
@@ -1703,8 +1703,8 @@ The 'flex-basis' property</h4>
 	Animatable: as 'width'
 	</pre>
 
-	Note: Authors are encouraged to control flexibility using the 'flex' shorthand
-	rather than with component properties,
+	Advisement: Authors are encouraged to control flexibility using the 'flex' shorthand
+	rather than with 'flex-basis' directly,
 	as the shorthand correctly resets any unspecified components
 	to accommodate <a href="#flex-common">common uses</a>.