Cleanup all the release notes

Fix grammar issues with release notes. Make the wording clearer for
a few of them as well.

Change-Id: If766f222c57f490276de717618ebb7102e7efdcb
Signed-off-by: Kyle Mestery <mestery@mestery.com>

releasenotes/notes/add-availability-zone-4440cf00be7c54ba.yaml

@@ -1,10 +1,10 @@
 ---
 prelude: >
-    Agent scheduling aware of availability zones is now supported.
+    DHCP and L3 Agent scheduling is availability zone aware.
 features:
-  - DHCP agent is assigned to an availability zone; network will be hosted by
-    the DHCP agent with availability zone which user specifies.
-  - L3 agent is assigned to an availability zone; router will be hosted by the
-    L3 agent with availability zone which user specifies. This supports the use
-    of availability zones with HA routers. DVR isn't supported now because L3HA
-    and DVR integration isn't finished.
+  - A DHCP agent is assigned to an availability zone; the network will be
+    hosted by the DHCP agent with availability zone specified by the user.
+  - An L3 agent is assigned to an availability zone; the router will be hosted
+    by the L3 agent with availability zone specified by the user. This supports
+    the use of availability zones with HA routers. DVR isn't supported now
+    because L3HA and DVR integration isn't finished.

releasenotes/notes/config-file-generation-2eafc6602d57178e.yaml

@@ -1,6 +1,6 @@
 ---
 prelude: >
-   Generation of sample Neutron core configuration files.
+   Core configuration files are automatically generated.
 features:
   - Neutron no longer includes static example configuration files. Instead,
     use tools/generate_config_file_samples.sh to generate them. The files are

releasenotes/notes/deprecate-router_id-34aca9ea5ee9e789.yaml

@@ -1,5 +1,3 @@
 ---
-prelude: >
-    Deprecate router_id option in order to prepare its removal in N cycle.
 upgrade:
-  - router_id option deprecation
+  - The router_id option is deprecated and will be removed in the 'N' cycle.

releasenotes/notes/hyperv-neutron-agent-decomposition-ae6a052aeb48c6ac.yaml

@@ -1,8 +1,8 @@
 ---
 upgrade:
-  - Hyper-V Neutron Agent has been fully decomposed from Neutron. Therefore, the
-    `neutron.plugins.hyperv.agent.security_groups_driver.HyperVSecurityGroupsDriver`
-    firewall driver has been deprecated and will be removed in the O cycle.
+  - The Hyper-V Neutron Agent has been fully decomposed from Neutron.
+    The `neutron.plugins.hyperv.agent.security_groups_driver.HyperVSecurityGroupsDriver`
+    firewall driver has been deprecated and will be removed in the 'O' cycle.
     Update the `neutron_hyperv_agent.conf` files on the Hyper-V nodes to
     use `hyperv.neutron.security_groups_driver.HyperVSecurityGroupsDriver`,
     which is the networking_hyperv security groups driver.

releasenotes/notes/oslo-reports-166a169037bf64f2.yaml

@@ -2,5 +2,5 @@
 prelude: >
     Neutron is integrated with Guru Meditation Reports library.
 features:
-  - Neutron services should now respond to SIGUSR2 signal by dumping valuable
-    debug information to standard error output.
+  - Neutron services should respond to SIGUSR2 signal by dumping valuable debug
+    information to standard error output.

releasenotes/notes/rm-notify-entry-points-aa442134a780469a.yaml

@@ -1,9 +1,8 @@
 ---
-prelude: |
-  oslo.messaging.notify.drivers entry points are deprecated
+prelude: >
+    oslo.messaging.notify.drivers entry points are deprecated
 other:
-  - |
-    The oslo.messaging.notify.drivers entry points that were left in tree for
+  - The oslo.messaging.notify.drivers entry points that were left in tree for
     backward compatibility with Icehouse are deprecated and will be removed
     after liberty-eol. Configure notifications using the oslo_messaging
     configuration options in neutron.conf.

releasenotes/notes/use-keystoneauth-24f309566001a16b.yaml

@@ -1,6 +1,5 @@
 ---
 upgrade:
-  - neutron now depends on keystoneauth instead of
-    keystoneclient.
+  - Neutron depends on keystoneauth instead of keystoneclient.
 features:
-  - neutron can now interact with keystone v3.
+  - Neutron can interact with keystone v3.