clock_nanosleep.2: wfix: s/clock_id/clockid/ throughout

Most other section 2 pages use 'clockid' as the name
of the 'clockid_t' argument.

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

man2/clock_nanosleep.2

@@ -30,7 +30,7 @@ clock_nanosleep \- high-resolution sleep with specifiable clock
 .B #include <time.h>
 .nf
 .PP
-.BI "int clock_nanosleep(clockid_t " clock_id ", int " flags ,
+.BI "int clock_nanosleep(clockid_t " clockid ", int " flags ,
 .BI "                    const struct timespec *" request ,
 .BI "                    struct timespec *" remain );
 .fi
@@ -73,7 +73,7 @@ struct timespec {
 .in
 .PP
 The
-.I clock_id
+.I clockid
 argument specifies the clock against which the sleep interval
 is to be measured.
 This argument can have one of the following values:
@@ -111,7 +111,7 @@ In addition, the CPU clock IDs returned by
 and
 .BR pthread_getcpuclockid (3)
 can also be passed in
-.IR clock_id .
+.IR clockid .
 .\" Sleeping against CLOCK_REALTIME_ALARM and CLOCK_BOOTTIME_ALARM
 .\" is also possible (tested), with CAP_WAKE_ALARM, but I'm not
 .\" sure if this is useful or needs to be documented.
@@ -122,7 +122,7 @@ is 0, then the value specified in
 .I request
 is interpreted as an interval relative to the current
 value of the clock specified by
-.IR clock_id .
+.IR clockid .
 .PP
 If
 .I flags
@@ -131,7 +131,7 @@ is
 then
 .I request
 is interpreted as an absolute time as measured by the clock,
-.IR clock_id .
+.IR clockid .
 If
 .I request
 is less than or equal to the current value of the clock,
@@ -188,15 +188,15 @@ field was not in the range 0 to 999999999 or
 was negative.
 .TP
 .B EINVAL
-.I clock_id
+.I clockid
 was invalid.
 .RB ( CLOCK_THREAD_CPUTIME_ID
 is not a permitted value for
-.IR clock_id .)
+.IR clockid .)
 .TP
 .B ENOTSUP
 The kernel does not support sleeping against this
-.IR clock_id .
+.IR clockid .
 .SH VERSIONS
 The
 .BR clock_nanosleep ()