pgsql: pg_dump docs: use escaped double-quotes, for Windows

pg_dump docs:  use escaped double-quotes, for Windows
On Unix, you can embed double-quotes in single-quotes, and via versa.
However, on Windows, you can only escape double-quotes in double-quotes,
so use that in the pg_dump -t/table example.
Backpatch to 9.3.
Report from Mike Toews

Branch
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REL9_3_STABLE

Details
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http://git.postgresql.org/pg/commitdiff/4d6ae6aaec5744f734735b9ab8acf29a4e97f151

Modified Files
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doc/src/sgml/ref/pg_dump.sgml |    2 +-
1 file changed, 1 insertion(+), 1 deletion(-)