pgsql: Document installing perltidy with cpanm

Document installing perltidy with cpanm

Installing with plain cpan failed for me recently, as the archive it
searched has been purged of old releases. However, you can give cpanm a
complete URL to the exact version you want to install, so document using
that.

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/e0d70a91a04b942980ab06bc471d2b5b65952459

Modified Files
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src/tools/pgindent/README | 2 ++
1 file changed, 2 insertions(+)