fix Issue 2639 - Hex and octal string values not completely specified

lex.dd

@@ -480,12 +480,12 @@ r"a" "bc"
 $(V1 \x61"bc")
 -----------------
 
-	The optional $(I StringPostfix) character gives a specific type
+	$(P The optional $(I StringPostfix) character gives a specific type
 	to the string, rather than it being inferred from the context.
 	This is useful when the type cannot be unambiguously inferred,
 	such as when overloading based on string type. The types corresponding
 	to the postfix characters are:
-	<p>
+	)
 
 	$(TABLE2 String Literal Postfix Characters,
 	$(THEAD Postfix, Type)
@@ -500,6 +500,10 @@ $(V1 \x61"bc")
 "hello"d  // dchar[]
 ---
 
+	$(P The string literals are assembled as UTF-8 char arrays,
+	and the postfix is applied
+	to convert to wchar or dchar as necessary as a final step.)
+
 	$(P String literals are read only. Writes to string literals
 	cannot always be detected, but cause undefined behavior.)