pgsql: Spell "startup process" with lower case in the documentation

Spell "startup process" with lower case in the documentation

Most uses were already lower case, so this just makes all user-visible
spellings consistent.

Bharath Rupireddy

The proposed patch also had analagous changes for the code comments,
but I decided that wasn't worth the churn.

Discussion:
https://www.postgresql.org/message-id/flat/CALj2ACW7%2Bv_0QBPoWB%3DqKr67JKC019Htm%3DX8sKewS17bOquefg%40mail.gmail.com

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/a59135a81aa781d126c48a516179e43dbb0d428a

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