sigaction.2: Minor fix: consistent sentence formatting in 'si_code' lists

Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>

man2/sigaction.2

@@ -504,23 +504,23 @@ for any signal, along with reason that the signal was generated.
 .RS 4
 .TP
 .B SI_USER
-.BR kill (2)
+.BR kill (2).
 .TP
 .B SI_KERNEL
 Sent by the kernel.
 .TP
 .B SI_QUEUE
-.BR sigqueue (3)
+.BR sigqueue (3).
 .TP
 .B SI_TIMER
-POSIX timer expired
+POSIX timer expired.
 .TP
 .BR SI_MESGQ " (since Linux 2.6.6)"
 POSIX message queue state changed; see
-.BR mq_notify (3)
+.BR mq_notify (3).
 .TP
 .B SI_ASYNCIO
-AIO completed
+AIO completed.
 .TP
 .B SI_SIGIO
 Queued
@@ -534,7 +534,7 @@ as described below).
 .BR SI_TKILL " (since Linux 2.4.19)"
 .BR tkill (2)
 or
-.BR tgkill (2)
+.BR tgkill (2).
 .\" SI_DETHREAD is defined in 2.6.9 sources, but isn't implemented
 .\" It appears to have been an idea that was tried during 2.5.6
 .\" through to 2.5.24 and then was backed out.
@@ -548,28 +548,28 @@ signal:
 .RS 4
 .TP
 .B ILL_ILLOPC
-illegal opcode
+Illegal opcode.
 .TP
 .B ILL_ILLOPN
-illegal operand
+Illegal operand.
 .TP
 .B ILL_ILLADR
-illegal addressing mode
+Illegal addressing mode.
 .TP
 .B ILL_ILLTRP
-illegal trap
+Illegal trap.
 .TP
 .B ILL_PRVOPC
-privileged opcode
+Privileged opcode.
 .TP
 .B ILL_PRVREG
-privileged register
+Privileged register.
 .TP
 .B ILL_COPROC
-coprocessor error
+Coprocessor error.
 .TP
 .B ILL_BADSTK
-internal stack error
+Internal stack error.
 .RE
 .PP
 The following values can be placed in
@@ -580,28 +580,28 @@ signal:
 .RS 4
 .TP
 .B FPE_INTDIV
-integer divide by zero
+Integer divide by zero.
 .TP
 .B FPE_INTOVF
-integer overflow
+Integer overflow.
 .TP
 .B FPE_FLTDIV
-floating-point divide by zero
+Floating-point divide by zero.
 .TP
 .B FPE_FLTOVF
-floating-point overflow
+Floating-point overflow.
 .TP
 .B FPE_FLTUND
-floating-point underflow
+Floating-point underflow.
 .TP
 .B FPE_FLTRES
-floating-point inexact result
+Floating-point inexact result.
 .TP
 .B FPE_FLTINV
-floating-point invalid operation
+Floating-point invalid operation.
 .TP
 .B FPE_FLTSUB
-subscript out of range
+Subscript out of range.
 .RE
 .PP
 The following values can be placed in
@@ -612,10 +612,10 @@ signal:
 .RS 4
 .TP
 .B SEGV_MAPERR
-address not mapped to object
+Address not mapped to object.
 .TP
 .B SEGV_ACCERR
-invalid permissions for mapped object
+Invalid permissions for mapped object.
 .RE
 .PP
 The following values can be placed in
@@ -626,13 +626,13 @@ signal:
 .RS 4
 .TP
 .B BUS_ADRALN
-invalid address alignment
+Invalid address alignment.
 .TP
 .B BUS_ADRERR
-nonexistent physical address
+Nonexistent physical address.
 .TP
 .B BUS_OBJERR
-object-specific hardware error
+Object-specific hardware error.
 .TP
 .BR BUS_MCEERR_AR " (since Linux 2.6.32)"
 Hardware memory error consumed on a machine check; action required.
@@ -649,16 +649,16 @@ signal:
 .RS 4
 .TP
 .B TRAP_BRKPT
-process breakpoint
+Process breakpoint.
 .TP
 .B TRAP_TRACE
-process trace trap
+Process trace trap.
 .TP
 .BR TRAP_BRANCH " (since Linux 2.4)"
-process taken branch trap
+Process taken branch trap.
 .TP
 .BR TRAP_HWBKPT " (since Linux 2.4)"
-hardware breakpoint/watchpoint
+Hardware breakpoint/watchpoint.
 .RE
 .PP
 The following values can be placed in
@@ -669,22 +669,22 @@ signal:
 .RS 4
 .TP
 .B CLD_EXITED
-child has exited
+Child has exited.
 .TP
 .B CLD_KILLED
-child was killed
+Child was killed.
 .TP
 .B CLD_DUMPED
-child terminated abnormally
+Child terminated abnormally.
 .TP
 .B CLD_TRAPPED
-traced child has trapped
+Traced child has trapped.
 .TP
 .B CLD_STOPPED
-child has stopped
+Child has stopped.
 .TP
 .BR CLD_CONTINUED " (since Linux 2.6.9)"
-stopped child has continued
+Stopped child has continued.
 .RE
 .PP
 The following values can be placed in
@@ -695,22 +695,22 @@ signal:
 .RS 4
 .TP
 .B POLL_IN
-data input available
+Data input available.
 .TP
 .B POLL_OUT
-output buffers available
+Output buffers available.
 .TP
 .B POLL_MSG
-input message available
+Input message available.
 .TP
 .B POLL_ERR
-I/O error
+I/O error.
 .TP
 .B POLL_PRI
-high priority input available
+High priority input available.
 .TP
 .B POLL_HUP
-device disconnected
+Device disconnected.
 .RE
 .PP
 The following value can be placed in
@@ -721,9 +721,9 @@ signal:
 .RS 4
 .TP
 .BR SYS_SECCOMP " (since Linux 3.5)"
-triggered by a
+Triggered by a
 .BR seccomp (2)
-filter rule
+filter rule.
 .RE
 .SH RETURN VALUE
 .BR sigaction ()