[css-text-3] Fix typo

Closes #5156

Author: frivoal

css-text-3/Overview.bs

@@ -3416,10 +3416,10 @@ Line Breaking Details</h3>
 
           Note: In some languages
           (such as English but not German),
-          it may appropriate to avoid having hyphenation opportunities in mixed case words,
+          it may be appropriate to avoid having hyphenation opportunities in mixed case words,
           as those may indicate proper nouns.
           This type of heuristic is however not mandated by this specification,
-          as is up to the User Agent and its language-specific hyphenation resource.
+          as it is up to the User Agent and its language-specific hyphenation resource.
     </dl>
 
     <p>Correct automatic hyphenation requires a hyphenation resource