doc/cephfs: update cephfs-shell link

Repair the link to cephfs-shell.rst in doc/cephfs/cephfs-shell.rst that
was broken in ceph#41165 when
doc/cephfs/cephfs-shell.rst was moved to doc/man/8/cephfs-shell.rst.

This commit is made in response to a request by Lander Duncan that was
made on the [ceph-users] mailing list, and can be seen here: https://lists.ceph.io/hyperkitty/list/[email protected]/thread/F7V4CWLIYCAJ4JXI2JLNY6QPCFPR4SLA/

Signed-off-by: Zac Dover <[email protected]>

Author: zdover23

doc/cephfs/mount-prerequisites.rst

@@ -2,11 +2,11 @@ Mount CephFS: Prerequisites
 ===========================
 
 You can use CephFS by mounting it to your local filesystem or by using
-`cephfs-shell`_. Mounting CephFS requires superuser privileges to trim
-dentries by issuing a remount of itself. CephFS can be mounted
-`using kernel`_ as well as `using FUSE`_. Both have their own
-advantages. Read the following section to understand more about both of
-these ways to mount CephFS.
+:ref:`cephfs-shell <cephfs-shell>`. Mounting CephFS requires superuser
+privileges to trim dentries by issuing a remount of itself. CephFS can be
+mounted `using kernel`_ as well as `using FUSE`_. Both have their own
+advantages. Read the following section to understand more about both of these
+ways to mount CephFS.
 
 For Windows CephFS mounts, please check the `ceph-dokan`_ page.
 
@@ -69,7 +69,7 @@ Ceph MON resides.
    individually, please check respective mount documents.
 
 .. _Client Authentication: ../client-auth
-.. _cephfs-shell: ../cephfs-shell
+.. _cephfs-shell: ..cephfs-shell
 .. _using kernel: ../mount-using-kernel-driver
 .. _using FUSE: ../mount-using-fuse
 .. _ceph-dokan: ../ceph-dokan

doc/man/8/cephfs-shell.rst

@@ -1,5 +1,7 @@
 :orphan:
 
+.. _cephfs-shell:
+
 ===================================================
 cephfs-shell -- Shell-like tool talking with CephFS
 ===================================================