Doc: Reset breaking changes and release notes for 9.0

docs/static/breaking-changes-80.asciidoc

@@ -1,6 +1,20 @@
 [[breaking-8.0]]
+=== Breaking changes in 8.0 and 8.x 
+
+[discrete]
+[[breaking-8.15]]
+=== Breaking changes in 8.15
+
+*New {ls} SNMP integration plugin*
+
+Prior to 8.15.0, {ls} bundled stand-alone versions of the `input-snmp` and `input-snmptrap` plugins by default. 
+When you upgrade to 8.15.0, the stand-alone plugins are replaced by the 4.0.0+ version contained in the new SNMP integration plugin.
+
+IMPORTANT: Before you upgrade to {ls} 8.15.0, be aware of {logstash-ref}/plugins-integrations-snmp.html#plugins-integrations-snmp-migration[behavioral and mapping differences] between stand-alone plugins and the new versions included in the {logstash-ref}/plugins-integrations-snmp.html[SNMP integration plugin].
+If you need to maintain current mappings for the `input-snmptrap` plugin, you have some options to {logstash-ref}/plugins-integrations-snmp.html#plugins-integrations-snmp-input-snmptrap-compat[preserve existing behavior].
+
+[discrete]
 === Breaking changes in 8.0
-Here are the breaking changes for 8.0.
 
 [discrete]
 [[security-on-8.0]]

docs/static/breaking-changes-90.asciidoc

@@ -0,0 +1,15 @@
+[discrete] 
+[[breaking-9.0]]
+=== Breaking changes in 9.0
+coming[9.0.0]
+
+[discrete]
+[[sample-change-9.0]]
+===== Breaking change number one (sample) 
+
+Include:
+
+* change
+* user impact/decription/value prop
+* link to relevant docs for more information
+

docs/static/redirects.asciidoc

@@ -1,7 +1,7 @@
 ["appendix",role="exclude",id="redirects"]
 = Deleted pages
 
-The following pages have moved or been deleted.
+The pages in this section have been deleted or moved from another location.
 
 // MULTILINE FILTER