pgsql: Update item description: < * CREATE TABLE AS can not determine

Log Message:
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Update item description:

< * CREATE TABLE AS can not determine column lengths from expressions [atttypmod]

* Allow CREATE TABLE AS to determine column lengths for complex
expressions like SELECT col1 || col2

Modified Files:
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pgsql/doc:
TODO (r1.1387 -> r1.1388)
(http://developer.postgresql.org/cvsweb.cgi/pgsql/doc/TODO.diff?r1=1.1387&amp;r2=1.1388)