fs: fix __sb_write_started() kerneldoc formatting

When running 'make htmldocs', I see the following warning:

  Documentation/filesystems/api-summary:14: ./include/linux/fs.h:1659: WARNING: Definition list ends without a blank line; unexpected unindent.

The official guidance [1] seems to be to use lists, which will prevent
both the "unexpected unindent" warning as well as ensure that each line
is formatted on a separate line in the HTML output instead of being
all considered a single paragraph.

[1]: https://docs.kernel.org/doc-guide/kernel-doc.html#return-values

Fixes: 8802e58 ("fs: create __sb_write_started() helper")
Cc: Amir Goldstein <amir73il@gmail.com>
Cc: Josef Bacik <josef@toxicpanda.com>
Cc: Jan Kara <jack@suse.cz>
Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
Link: https://lore.kernel.org/r/20231228100608.3123987-1-vegard.nossum@oracle.com
Signed-off-by: Christian Brauner <brauner@kernel.org>

Author: vegard

include/linux/fs.h

@@ -1650,9 +1650,9 @@ static inline bool __sb_start_write_trylock(struct super_block *sb, int level)
  * @sb: the super we write to
  * @level: the freeze level
  *
- * > 0 sb freeze level is held
- *   0 sb freeze level is not held
- * < 0 !CONFIG_LOCKDEP/LOCK_STATE_UNKNOWN
+ * * > 0 - sb freeze level is held
+ * *   0 - sb freeze level is not held
+ * * < 0 - !CONFIG_LOCKDEP/LOCK_STATE_UNKNOWN
  */
 static inline int __sb_write_started(const struct super_block *sb, int level)
 {