CLEANUP: assorted typo fixes in the code and comments

This is 8th iteration of typo fixes
diff --git a/scripts/backport b/scripts/backport
index 0dc102c..4f60140 100755
--- a/scripts/backport
+++ b/scripts/backport
@@ -88,7 +88,7 @@
 
 # backports commit "$1" with a signed-off by tag. In case of failure, aborts
 # the change and returns non-zero. Unneeded cherry-picks do return an error
-# because we don't want to accidently backport the latest commit instead of
+# because we don't want to accidentally backport the latest commit instead of
 # this one, and we don't know this one's ID.
 backport_commit() {
 	local empty=1