Fix documentation for org-capture template expansion

* doc/org.texi (Template expansion): Fix typo.

TINYCHANGE

doc/org.texi

@@ -7166,7 +7166,7 @@ dynamic insertion of content.  The templates are expanded in the order given her
             @r{You may specify a default value and a completion table with}
             @r{%^@{prompt|default|completion2|completion3...@}.}
             @r{The arrow keys access a prompt-specific history.}
-%\n         @r{Insert the text entered at the nth %^@{@var{prompt}@}, where @code{n} is}
+%\\n        @r{Insert the text entered at the nth %^@{@var{prompt}@}, where @code{n} is}
             @r{a number, starting from 1.}
 %?          @r{After completing the template, position cursor here.}
 @end smallexample