[css-variables-1] Use I18n-suggested text, fix w3c#7133

Author: svgeesus

css-variables-1/Overview.bs

@@ -172,8 +172,14 @@ Defining Custom Properties: the '--*' family of properties</h2>
 		to determine if two strings are equal,
 		to avoid the complexities and pitfalls of unicode normalization and locale-specific collation.
 
-		Different OSes or input methods can sometimes output visually-identical text with different codepoints,
-		so authors should be aware of this potential hazard.
+		Operating systems, keyboards, or input methods
+		sometimes encode visually-identical text
+		using different codepoint sequences.
+		Authors are advised to choose variable names
+		that avoid potential confusion
+		or to use escapes and other means
+		to ensure that similar appearing sequences are identical.
+		See Section 2.3 in [[CHARMOD-NORM]] for examples.
 	</div>
 
 	Custom properties are <strong>not</strong> reset by the 'all' property.