Обсуждение: pgsql: Fix translation of special characters in psql's LaTeX outputmod

Fix translation of special characters in psql's LaTeX output modes.

latex_escaped_print() mistranslated \ and failed to provide any translation
for # ^ and ~, all of which would typically lead to LaTeX document syntax
errors.  In addition it didn't translate < > and |, which would typically
render as unexpected characters.

To some extent this represents shortcomings in ancient versions of LaTeX,
which if memory serves had no easy way to render these control characters
as ASCII text.  But that's been fixed for, um, decades.  In any case there
is no value in emitting guaranteed-to-fail output for these characters.

Noted while fooling with test cases added by commit 9a98984f4.  Back-patch
the code change to all supported versions.

Branch
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REL9_6_STABLE

Details
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https://git.postgresql.org/pg/commitdiff/ac305ff8c3dfe44d3441297f665ac3c602a87199

Modified Files
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src/fe_utils/print.c | 36 ++++++++++++++++++++++++++++++------
1 file changed, 30 insertions(+), 6 deletions(-)