fix some comments typos (#315)

chunkenc/xor.go

@@ -13,7 +13,7 @@
 
 // The code in this file was largely written by Damian Gryski as part of
 // https://github.com/dgryski/go-tsz and published under the license below.
-// It was modified to accomodate reading from byte slices without modifying
+// It was modified to accommodate reading from byte slices without modifying
 // the underlying bytes, which would panic when reading from mmaped
 // read-only byte slices.
 

head_test.go

@@ -631,7 +631,7 @@ func TestComputeChunkEndTime(t *testing.T) {
 			max:   1000,
 			res:   1000,
 		},
-		// Catch divison by zero for cur == start. Strictly not a possible case.
+		// Catch division by zero for cur == start. Strictly not a possible case.
 		{
 			start: 100,
 			cur:   100,

wal.go

@@ -418,7 +418,7 @@ func (w *SegmentWAL) Truncate(mint int64, keep func(uint64) bool) error {
 	}
 
 	// The file object of csf still holds the name before rename. Recreate it so
-	// subsequent truncations do not look at a non-existant file name.
+	// subsequent truncations do not look at a non-existent file name.
 	csf.File, err = w.openSegmentFile(candidates[0].Name())
 	if err != nil {
 		return err
@@ -1015,7 +1015,7 @@ func (r *walReader) at() (WALEntryType, byte, []byte) {
 }
 
 // next returns decodes the next entry pair and returns true
-// if it was succesful.
+// if it was successful.
 func (r *walReader) next() bool {
 	if r.cur >= len(r.files) {
 		return false