mseal: fix typo and style in documentation

Correct a typo in the mseal documentation.

Link: https://lkml.kernel.org/r/20250318115521.11654-1-takumaw1990@gmail.com
Signed-off-by: Takuma Watanabe <takumaw1990@gmail.com>
Cc: Jeff Xu <jeffxu@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Author: takumaw

Documentation/userspace-api/mseal.rst

@@ -27,7 +27,7 @@ SYSCALL
 =======
 mseal syscall signature
 -----------------------
-   ``int mseal(void \* addr, size_t len, unsigned long flags)``
+   ``int mseal(void *addr, size_t len, unsigned long flags)``
 
    **addr**/**len**: virtual memory address range.
       The address range set by **addr**/**len** must meet: