CLEANUP: assorted typo fixes in the code and comments

This is fifth iteration of typo fixes
diff --git a/contrib/spoa_example/include/spoe_types.h b/contrib/spoa_example/include/spoe_types.h
index 8f93edd..a986227 100644
--- a/contrib/spoa_example/include/spoe_types.h
+++ b/contrib/spoa_example/include/spoe_types.h
@@ -100,7 +100,7 @@
 	SPOE_CTX_ERRS,
 };
 
-/* Errors triggerd by SPOE applet */
+/* Errors triggered by SPOE applet */
 enum spoe_frame_error {
 	SPOE_FRM_ERR_NONE = 0,
 	SPOE_FRM_ERR_IO,