[COMMITTERS] pgsql: Doc: clarify wording about tool requirements insourcerepo.sgml.

Doc: clarify wording about tool requirements in sourcerepo.sgml.

Original wording had confusingly vague antecedent for "they", so replace
that with a more repetitive but clearer formulation.  In passing, make the
link to the installation requirements section more specific.  Per gripe
from Martin Mai, though this is not the fix he initially proposed.

Discussion: https://postgr.es/m/CAN_NWRu-cWuNaiXUjV3m4H-riWURuPW=j21bSaLADs6rjjzXgQ@mail.gmail.com

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/3834abe90c7359319d1909fdb69a40963276a690

Modified Files
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doc/src/sgml/sourcerepo.sgml | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)