Typo fix. "CVS" is not the same thing as "CSV".

src/backend/commands/copy.c

@@ -2654,7 +2654,7 @@ CopyReadLineText(CopyState cstate)
 				 * something other than a period.  In non-CSV mode, anything
 				 * after a backslash is special, so we skip over that second
 				 * character too.  If we didn't do that \\. would be
-				 * considered an eof-of copy, while in non-CVS mode it is a
+				 * considered an eof-of copy, while in non-CSV mode it is a
 				 * literal backslash followed by a period.	In CSV mode,
 				 * backslashes are not special, so we want to process the
 				 * character after the backslash just like a normal character,