Man page white space and spelling corrections

Correct some misspelled words and grammatical errors, and remove
trailing white space in the man pages.

Signed-off-by: Ned Bass <bass6@llnl.gov>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #4115

man/man5/zfs-events.5

@@ -280,7 +280,7 @@ Issued when there is an I/O failure in a vdev in the pool.
 \fBprobe_failure\fR
 .ad
 .RS 12n
-Issued when a probe fails on a vdev. This would occur if a vdeev
+Issued when a probe fails on a vdev. This would occur if a vdev
 have been kicked from the system outside of ZFS (such as the kernel
 have removed the device).
 .RE
@@ -443,7 +443,7 @@ Physical FRU location.
 \fBvdev_state\fR
 .ad
 .RS 12n
-State of vdev (0=uninitialized, 1=closed, 2=offline, 3=removed, 4=failed to open, 5=faulted, 6=degraded, 7=healty).
+State of vdev (0=uninitialized, 1=closed, 2=offline, 3=removed, 4=failed to open, 5=faulted, 6=degraded, 7=healthy).
 .RE
 
 .sp

man/man5/zfs-module-parameters.5

@@ -1169,7 +1169,7 @@ Defines a threshold at which metaslab groups should be eligible for
 allocations.  The value is expressed as a percentage of free space
 beyond which a metaslab group is always eligible for allocations.
 If a metaslab group's free space is less than or equal to the
-the threshold, the allocator will avoid allocating to that group
+threshold, the allocator will avoid allocating to that group
 unless all groups in the pool have reached the threshold.  Once all
 groups have reached the threshold, all groups are allowed to accept
 allocations.  The default value of 0 disables the feature and causes
@@ -1582,7 +1582,7 @@ Default value: \fB1,048,576\fR.
 \fBzio_delay_max\fR (int)
 .ad
 .RS 12n
-Max zio millisec delay before posting event
+Max zio millisecond delay before posting event
 .sp
 Default value: \fB30,000\fR.
 .RE

man/man5/zpool-features.5

@@ -402,7 +402,7 @@ or smaller can take advantage of this feature.
 
 When this feature is enabled, the contents of highly-compressible blocks are
 stored in the block "pointer" itself (a misnomer in this case, as it contains
-the compresseed data, rather than a pointer to its location on disk).  Thus
+the compressed data, rather than a pointer to its location on disk).  Thus
 the space of the block (one sector, typically 512 bytes or 4KB) is saved,
 and no additional i/o is needed to read and write the data block.