NFSD: nfsd-io-modes: Wrap shell snippets in literal code blocks

Sphinx reports htmldocs indentation warnings:

Documentation/filesystems/nfs/nfsd-io-modes.rst:29: ERROR: Unexpected indentation. [docutils]
Documentation/filesystems/nfs/nfsd-io-modes.rst:34: ERROR: Unexpected indentation. [docutils]

Fix these by wrapping shell snippets in literal code blocks.

Fixes: fa8d4e6 ("NFSD: add Documentation/filesystems/nfs/nfsd-io-modes.rst")
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Closes: https://lore.kernel.org/linux-next/20251202152506.7a2d2d41@canb.auug.org.au/
Signed-off-by: Bagas Sanjaya <bagasdotme@gmail.com>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
Tested-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

Author: bagasme

Documentation/filesystems/nfs/nfsd-io-modes.rst

@@ -25,12 +25,14 @@ Based on the configured settings, NFSD's IO will either be:
 - not cached stable_how=NFS_UNSTABLE (NFSD_IO_DIRECT=2)
 
 To set an NFSD IO mode, write a supported value (0 - 2) to the
-corresponding IO operation's debugfs interface, e.g.:
+corresponding IO operation's debugfs interface, e.g.::
+
   echo 2 > /sys/kernel/debug/nfsd/io_cache_read
   echo 2 > /sys/kernel/debug/nfsd/io_cache_write
 
 To check which IO mode NFSD is using for READ or WRITE, simply read the
-corresponding IO operation's debugfs interface, e.g.:
+corresponding IO operation's debugfs interface, e.g.::
+
   cat /sys/kernel/debug/nfsd/io_cache_read
   cat /sys/kernel/debug/nfsd/io_cache_write
 
@@ -128,17 +130,19 @@ Tracing:
     misaligned READ to the next DIO-aligned block (on either end of the
     original READ, as needed).
 
-    This combination of trace events is useful for READs:
-    echo 1 > /sys/kernel/tracing/events/nfsd/nfsd_read_vector/enable
-    echo 1 > /sys/kernel/tracing/events/nfsd/nfsd_read_direct/enable
-    echo 1 > /sys/kernel/tracing/events/nfsd/nfsd_read_io_done/enable
-    echo 1 > /sys/kernel/tracing/events/xfs/xfs_file_direct_read/enable
+    This combination of trace events is useful for READs::
+
+      echo 1 > /sys/kernel/tracing/events/nfsd/nfsd_read_vector/enable
+      echo 1 > /sys/kernel/tracing/events/nfsd/nfsd_read_direct/enable
+      echo 1 > /sys/kernel/tracing/events/nfsd/nfsd_read_io_done/enable
+      echo 1 > /sys/kernel/tracing/events/xfs/xfs_file_direct_read/enable
 
     The nfsd_write_direct trace event shows how NFSD splits a given
     misaligned WRITE into a DIO-aligned middle segment.
 
-    This combination of trace events is useful for WRITEs:
-    echo 1 > /sys/kernel/tracing/events/nfsd/nfsd_write_opened/enable
-    echo 1 > /sys/kernel/tracing/events/nfsd/nfsd_write_direct/enable
-    echo 1 > /sys/kernel/tracing/events/nfsd/nfsd_write_io_done/enable
-    echo 1 > /sys/kernel/tracing/events/xfs/xfs_file_direct_write/enable
+    This combination of trace events is useful for WRITEs::
+
+      echo 1 > /sys/kernel/tracing/events/nfsd/nfsd_write_opened/enable
+      echo 1 > /sys/kernel/tracing/events/nfsd/nfsd_write_direct/enable
+      echo 1 > /sys/kernel/tracing/events/nfsd/nfsd_write_io_done/enable
+      echo 1 > /sys/kernel/tracing/events/xfs/xfs_file_direct_write/enable