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/tests/inode-tests.c b/fs/btrfs/tests/inode-tests.c
index 863a6a3..8a25fe8 100644
--- a/fs/btrfs/tests/inode-tests.c
+++ b/fs/btrfs/tests/inode-tests.c
@@ -264,7 +264,7 @@
 
 	/*
 	 * We will just free a dummy node if it's ref count is 2 so we need an
-	 * extra ref so our searches don't accidently release our page.
+	 * extra ref so our searches don't accidentally release our page.
 	 */
 	extent_buffer_get(root->node);
 	btrfs_set_header_nritems(root->node, 0);