Add missing word

Doc/lib/libunicodedata.tex

@@ -108,7 +108,7 @@ decomposition, and translates each character into its decomposed form.
 Normal form C (NFC) first applies a canonical decomposition, then
 composes pre-combined characters again.
 
-In addition to these two forms, there two additional normal forms
+In addition to these two forms, there are two additional normal forms
 based on compatibility equivalence. In Unicode, certain characters are
 supported which normally would be unified with other characters. For
 example, U+2160 (ROMAN NUMERAL ONE) is really the same thing as U+0049
@@ -139,3 +139,4 @@ the Unicode database (such as IDNA).
 
 \versionadded{2.5}
 \end{datadesc}
+