docs: f2fs: fix text alignment

The docs build was generating this warning:

  Documentation/filesystems/f2fs.rst:306: WARNING: Block quote ends without a blank line; unexpected unindent.

Remove the extra white space that was confusing sphinx.

Fixes: 151b1982 (f2fs: compress: add nocompress extensions support)
Signed-off-by: Fengnan Chang <changfengnan@vivo.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Link: https://lore.kernel.org/r/20211023025833.216030-1-changfengnan@vivo.comSigned-off-by: Jonathan Corbet <corbet@lwn.net>

Documentation/filesystems/f2fs.rst

@@ -283,7 +283,7 @@ compress_extension=%s	 Support adding specified extension, so that f2fs can enab
 			 For other files, we can still enable compression via ioctl.
 			 Note that, there is one reserved special extension '*', it
 			 can be set to enable compression for all files.
-nocompress_extension=%s	   Support adding specified extension, so that f2fs can disable
+nocompress_extension=%s	 Support adding specified extension, so that f2fs can disable
 			 compression on those corresponding files, just contrary to compression extension.
 			 If you know exactly which files cannot be compressed, you can use this.
 			 The same extension name can't appear in both compress and nocompress