pgsql: Rename two functions that wake up other processes

Rename two functions that wake up other processes

Instead of talking about setting latches, which is a pretty low-level
mechanism, emphasize that they wake up other processes.

This is in preparation for replacing Latches with a new abstraction.
That's still work in progress, but this seems a little tidier anyway,
so let's get this refactoring out of the way already.

Discussion: https://www.postgresql.org/message-id/391abe21-413e-4d91-a650-b663af49500c%40iki.fi

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/368d8270c838a6c328fc24418603cb172b5e0390

Modified Files
--------------
src/backend/access/transam/xlog.c         | 4 ++--
src/backend/access/transam/xlogrecovery.c | 2 +-
src/backend/access/transam/xlogwait.c     | 2 +-
src/backend/postmaster/walsummarizer.c    | 4 ++--
src/include/access/xlogwait.h             | 2 +-
src/include/postmaster/walsummarizer.h    | 2 +-
6 files changed, 8 insertions(+), 8 deletions(-)