maint: Use Octave coding conventions for cuddling parentheses in doc directory * OctaveFAQ.texi, basics.txi, container.txi, contrib.txi, diagperm.txi, diffeq.txi, dynamic.txi, errors.txi, eval.txi, expr.txi, func.txi, geometry.txi, interp.txi, intro.txi, numbers.txi, oop.txi, plot.txi, poly.txi, quad.txi, set.txi, sparse.txi, stmt.txi, testfun.txi, vectorize.txi, refcard.tex: Use Octave coding conventions for cuddling parentheses.

--- a/doc/interpreter/errors.txi
+++ b/doc/interpreter/errors.txi
@@ -63,7 +63,7 @@
 @group
 function f (arg1)
   if (nargin == 0)
-    error("not enough input arguments");
+    error ("not enough input arguments");
   endif
 endfunction
 @end group