btrfs: fix string and comment grammatical issues and typos

Signed-off-by: Nicholas D Steeves <nsteeves@gmail.com>
Signed-off-by: David Sterba <dsterba@suse.com>
diff --git a/fs/btrfs/backref.c b/fs/btrfs/backref.c
index 80e8472..b8b5987 100644
--- a/fs/btrfs/backref.c
+++ b/fs/btrfs/backref.c
@@ -1939,7 +1939,7 @@
  * from ipath->fspath->val[i].
  * when it returns, there are ipath->fspath->elem_cnt number of paths available
  * in ipath->fspath->val[]. when the allocated space wasn't sufficient, the
- * number of missed paths in recored in ipath->fspath->elem_missed, otherwise,
+ * number of missed paths is recorded in ipath->fspath->elem_missed, otherwise,
  * it's zero. ipath->fspath->bytes_missing holds the number of bytes that would
  * have been needed to return all paths.
  */