Note UTF-8 array truncation issue

Author: mbtaylor

VOTable.tex

@@ -410,6 +410,9 @@ \subsection{Primitives}
 are equal.
 This means that a single (non-array) \literalvalue{char}
 is capable of storing a 7-bit ASCII character only.
+Strings must not be truncated mid-character
+so truncation of a string to fit a fixed-length char array may result in
+unused bytes at the end of the array.
 
 For historical reasons the \literalvalue{unicodeChar} type can also be used
 for character storage, but from VOTable 1.6 this type is deprecated.