clarify language around ::first-letter

Author: dauwhe

css-inline-3/Overview.bs

@@ -393,11 +393,11 @@ Raised Initial Letters</h4>
 	they may include punctuation or a sequence of characters which
 	are perceived by the user to be a single typographic unit.
 	The <code>::first-letter</code> pseudo-element, as defined in [[SELECT]],
-	can be used to select an <a>initial letter</a>.
+	can be used to select the character(s) to be formatted as <a>initial letters</a>.
 
 	Authors who need more control over which characters are included in an initial letter,
 	or who want to apply initial-letter formatting to replaced elements or multiple words
-	can also apply the 'initial-letter' property to the first inline-level child of a block container.
+	can alternately apply the 'initial-letter' property to the first inline-level child of a block container.
 
 	<div class="example">
 	<pre>
@@ -416,7 +416,8 @@ Raised Initial Letters</h4>
 
 <h4 id="initial-letter-punctuation">Initial Letter Punctuation</h4>
 
-Since <code>::first-letter</code> selects punctuation before or after the first letter, these characters are included in the initial-letter.
+	Since ''::first-letter'' selects punctuation before or after the first letter,
+	these characters are included in the initial-letter when ''::first-letter'' is used.
 
 	<figure>
 		<img src="images/initial-letter-punctuation-quote.png" width="604"