seqlock: fix scoped_seqlock_read kernel-doc

seqlock: fix scoped_seqlock_read kernel-doc

Eliminate all kernel-doc warnings in seqlock.h:

- correct the macro to have "()" immediately following the macro name
- don't include the macro parameters in the short description (first line)
- make the parameter names in the comments match the actual macro
  parameter names.
- use "::" for the Example

WARNING: include/linux/seqlock.h:1341 This comment starts with '/**', but isn't a kernel-doc comment.
 * scoped_seqlock_read (lock, ss_state) - execute the read side critical
Documentation/locking/seqlock:242: include/linux/seqlock.h:1351: WARNING:
  Definition list ends without a blank line; unexpected unindent. [docutils]
Warning: include/linux/seqlock.h:1357 function parameter '_seqlock' not described in 'scoped_seqlock_read'
Warning: include/linux/seqlock.h:1357 function parameter '_target' not described in 'scoped_seqlock_read'

Fixes: cc39f3872c08 ("seqlock: Introduce scoped_seqlock_read()")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20260123183749.3997533-1-rdunlap@infradead.org