Merge pull request #14322 from nextcloud/backport/14310/stable33

[stable33] fix(admin-manual): correct typos in upgrade docs and release schedule

Author: miaulalala

admin_manual/maintenance/upgrade.rst

@@ -8,7 +8,7 @@ Overview
 The approach used to upgrade your Nextcloud Server depends on your installation type. This
 manual mainly focuses on the methods that apply to an Archive based installation. If you installed
 using Snap, Docker, a pre-built VM, or a package management tool then refer to the installation
-and update instructions for that installation method for the most accurate upgrading inststructions
+and update instructions for that installation method for the most accurate upgrading instructions
 (generally located at the distribution point for the install method you chose).
 
 There are two ways to upgrade an Archive based Nextcloud Server deployment:

admin_manual/release_schedule.rst

@@ -56,7 +56,7 @@ A specific maintenance release is indicated by the last part of the version numb
 Release schedule
 ----------------
 
-New **major** releases of Nextcloud Server are published approximiately every sixteen weeks.
+New **major** releases of Nextcloud Server are published approximately every sixteen weeks.
 
 New **maintenance** releases are published approximately every four weeks.