pg_dump: Add const decorations
Add const decorations to the *info arguments of the dump* functions,
to clarify that they don't modify that argument. Many other nearby
functions modify their arguments, so this can help clarify these
different APIs a bit.
Discussion: https://www.postgresql.org/message-id/flat/
012d3030-9a2c-99a1-ed2d-
988978b5632f%40enterprisedb.com