docs: replace "stable storage" with "durable" in descriptions

For PG, "durable storage" has a clear meaning, while "stable storage"
does not, so use the former.

Discussion: https://postgr.es/m/20200817165222.GA31806@momjian.us

Backpatch-through: 9.5

diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index d0350dffd3ef83dfac58016e36fe5f596b0a66fb..15180b6509654bc04fd37bce9217ee75ef81669e 100644 (file)
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -2316,7 +2316,7 @@ include_dir 'conf.d'
         ensure data preservation even if a standby instance of
         <productname>PostgreSQL</> were to crash, but not if the standby
         suffers an operating-system-level crash, since the data has not
-        necessarily reached stable storage on the standby.
+        necessarily reached durable storage on the standby.
         Finally, the setting <literal>local</> causes commits to wait for
         local flush to disk, but not for replication.  This is not usually
         desirable when synchronous replication is in use, but is provided for