[css-pseudo-4] Wording tweaks from frivoal.

Author: fantasai

css-pseudo-4/Overview.bs

@@ -391,7 +391,7 @@ First-Letter Text: ''::first-letter'' pseudo-element and its ''::prefix'' and ''
   is represented by the <dfn for="::first-letter">::prefix</dfn>
   sub-[=pseudo-element=] of the ''::first-letter'' [=pseudo-element=]
   (''::first-letter::prefix'');
-  and following punctuation
+  and such following punctuation
   is represented by the <dfn for="::first-letter">::postfix</dfn>
   sub-[=pseudo-element=] of the ''::first-letter'' [=pseudo-element=]
   (''::first-letter::postfix'').
@@ -479,7 +479,7 @@ Inheritance and Box Tree Structure of the First-Letter Pseudo-elements</h4>
     </pre>
   </div>
 
-  If any ''::first-letter::prefix'' or ''::first-letter::postfix'' [=pseudo-elements=] are required,
+  If any ''::first-letter::prefix'' or ''::first-letter::postfix'' [=pseudo-elements=] exist,
   they are nested within the innermost ''::first-letter'',
   and otherwise interpreted similar to ''::first-letter'' itself.
 
@@ -532,7 +532,7 @@ Styling the First-Letter Pseudo-elements</h4>
   In CSS a ''::first-letter'' [=pseudo-element=]
   (and its ''::prefix'' and ''::postfix'' sub-elements)
   is similar to an [=inline box=].
-  The following properties that apply to
+  The following properties apply to
   ''::first-letter'', ''::first-letter::prefix'', and ''::first-letter::postfix''
   pseudo-elements: