CLEANUP: assorted typo fixes in the code and comments

This is fifth iteration of typo fixes
diff --git a/contrib/deviceatlas/dac.h b/contrib/deviceatlas/dac.h
index 4e0189a..92a9396 100644
--- a/contrib/deviceatlas/dac.h
+++ b/contrib/deviceatlas/dac.h
@@ -70,7 +70,7 @@
 enum da_severity {
     DA_SEV_FATAL, /* The operation will not continue, and the operation will return an error. */
     DA_SEV_ERROR, /* An error occurred, but the API call will return at least some valid information */
-    DA_SEV_WARN,  /* An unexpected event occured, but the system dealt with it */
+    DA_SEV_WARN,  /* An unexpected event occurred, but the system dealt with it */
     DA_SEV_INFO   /* An informational message. */
 };
 /* Forward references to tagged types */