pgsql: Update .abi-compliance-history for change to TransitionCaptureSt

Update .abi-compliance-history for change to TransitionCaptureState.

As noted in the commit message for b4307ae2e54, the change to the
TransitionCaptureState structure is nominally an ABI break, but it is
not expected to affect any third-party code. Therefore, add it to the
.abi-compliance-history file.

Discussion: https://postgr.es/m/19380-4e293be2b4007248%40postgresql.org
Backpatch-through: 15-18

Branch
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REL_15_STABLE

Details
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https://git.postgresql.org/pg/commitdiff/7023650429e970d7603e398b2b216b8abaf30ec9

Modified Files
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.abi-compliance-history | 11 +++++++++++
1 file changed, 11 insertions(+)