Release notes of 9.0~9.3 mentioning recovery_min_apply_delay incorrectly

Hi all,

While doing a git grep on recovery_min_apply_delay I noticed the following:
$ git grep recovery_min_apply -- *release*.sgml
src/sgml/release-9.0.sgml:      that <varname>recovery_min_apply_delay</> failed to delay application
src/sgml/release-9.1.sgml:      that <varname>recovery_min_apply_delay</> failed to delay application
src/sgml/release-9.2.sgml:      that <varname>recovery_min_apply_delay</> failed to delay application
src/sgml/release-9.3.sgml:      that <varname>recovery_min_apply_delay</> failed to delay application
src/sgml/release-9.4.sgml:      Avoid busy-waiting with short <literal>recovery_min_apply_delay</>

This is obviously incorrect because recovery_min_apply_delay has been only introduced in 9.4. The culprit is visibly the commit message of 8049839 and others that mentioned the parameter, though the patch applied does nothing about it. Please see attached a patch to fix that.

--
Michael