doc: Fix sphinx warnings

doc/cephadm/services/snmp-gateway.rst: Don't use double backticks for
links. Makes it a link instead of rendering syntax verbatim.
Also for consistency use single backticks for links instead of a plain
trailing underscore.
Improve language of opening sentence.

doc/dev/cephfs-mirroring.rst: Add missing empty line before preformatted
blocks. No change in rendered docs.

doc/mgr/telemetry.rst: Fix external link syntax. Makes it a link instead
of rendering syntax and pointing to non-existing link.

Signed-off-by: Ville Ojamo <[email protected]>

Author: bluikko

doc/cephadm/services/snmp-gateway.rst

@@ -2,10 +2,10 @@
 SNMP Gateway Service
 ====================
 
-SNMP_ is still a widely used protocol, to monitor distributed systems and devices across a variety of hardware
-and software platforms. Ceph's SNMP integration focuses on forwarding alerts from its Prometheus Alertmanager
+`SNMP`_ is a widely used protocol for monitoring distributed systems and devices.
+Ceph's SNMP integration focuses on forwarding alerts from its Prometheus Alertmanager
 cluster to a gateway daemon. The gateway daemon transforms the alert into an SNMP Notification and sends
-it on to a designated SNMP management platform. The gateway daemon is from the ``snmp_notifier``_ project,
+it on to a designated SNMP management platform. The gateway daemon is from the `snmp_notifier`_ project,
 which provides SNMP V2c and V3 support (authentication and encryption).
 
 Ceph's SNMP gateway service deploys one instance of the gateway by default. You may increase this
@@ -159,13 +159,13 @@ with a credentials file of the following form:
 AlertManager Integration
 ========================
 When an SNMP gateway service is deployed or updated, the Prometheus Alertmanager configuration is automatically updated to forward any
-alert that has an OID_ label to the SNMP gateway daemon for processing.
+alert that has an `OID`_ label to the SNMP gateway daemon for processing.
 
 .. _OID: https://en.wikipedia.org/wiki/Object_identifier
 
 Implementing the MIB
 ======================
 To make sense of SNMP notifications and traps, you'll need to apply the MIB to your SNMP management platform. The MIB (``CEPH-MIB.txt``) can
-downloaded from the main Ceph GitHub repository_
+downloaded from the main Ceph GitHub `repository`_
 
 .. _repository: https://github.com/ceph/ceph/tree/master/monitoring/snmp

doc/dev/cephfs-mirroring.rst

@@ -387,6 +387,7 @@ status. Commands of this kind take the form ``filesystem-name@filesystem-id peer
 .. prompt:: bash $
 
    ceph --admin-daemon /var/run/ceph/cephfs-mirror.asok fs mirror peer status cephfs@360 a2dc7784-e7a1-4723-b103-03ee8d8768f8
+
 ::
 
   {
@@ -432,6 +433,7 @@ status:
 
    ceph fs snapshot mirror add cephfs /f0
    ceph --admin-daemon /var/run/ceph/cephfs-mirror.asok fs mirror peer status cephfs@360 a2dc7784-e7a1-4723-b103-03ee8d8768f8
+
 ::
 
   {
@@ -470,6 +472,7 @@ mapped to use, run a command of the following form:
 .. prompt:: bash $
 
    ceph fs snapshot mirror dirmap cephfs /d0/d1/d2
+
 ::
 
   {
@@ -489,6 +492,7 @@ If no mirror daemons are running, the same command shows the following:
 .. prompt:: bash $
 
    ceph fs snapshot mirror dirmap cephfs /d0/d1/d2
+
 ::
 
   {

doc/mgr/telemetry.rst

@@ -65,7 +65,7 @@ and other parameters that help the project develop a better understanding of
 the way Ceph is used.
 
 Data is sent secured to
-`https://telemetry.ceph.com<https://telemetry.ceph.com>`_.
+`https://telemetry.ceph.com <https://telemetry.ceph.com>`_.
 
 Individual channels can be enabled or disabled by running the following
 commands: