Redo of PR#5345. Fixed spelling and typographical errors found by CodeSpell.

Signed-off-by: Shaun Case <warmsocks@gmail.com>
Signed-off-by: Dave Rodgman <dave.rodgman@arm.com>
diff --git a/SECURITY.md b/SECURITY.md
index bd18f6c..26b77ab 100644
--- a/SECURITY.md
+++ b/SECURITY.md
@@ -6,7 +6,7 @@
 
 ## Security Incident Handling Process
 
-Our security process is detailled in our
+Our security process is detailed in our
 [security
 center](https://developer.trustedfirmware.org/w/mbed-tls/security-center/).