Construct a text node by computing an expression.
The following construct(s) refer to this construct:
A CompTextConstructor constructs a text node by computing
the enclosed expression. This expression is evaluated and, after atomization,
converted into a sequence of atomic values each of which is cast into a string
and concatenated with a space character between each pair of values. If the
result of the expression after atomization is an empty sequence, no text node
is constructed.
This is the XQuery version of the classic example of printing "Hello World":
text{"Hello World"}