pgsql: doc: Tell about "vcregress taptest" for regression tests on Wind

doc: Tell about "vcregress taptest" for regression tests on Windows

There was no mention of this command in the documentation, and it is
useful to run the TAP tests of a target source directory.

Author: Yugo Nagata
Discussion: https://postgr.es/m/20230925153204.926d685d347ee1c8f527090c@sraoss.co.jp
Backpatch-through: 11

Branch
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REL_11_STABLE

Details
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https://git.postgresql.org/pg/commitdiff/6181eca090da350580e3dcea378cf3f85b1a54e2

Modified Files
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doc/src/sgml/install-windows.sgml | 14 +++++++++++---
1 file changed, 11 insertions(+), 3 deletions(-)