Copy edit security.md

Make minor changes to file for precise language.

Author: Amanda Butler

docs/reference/api/security/security.md

@@ -2,14 +2,14 @@
 
 Security on Arm Mbed OS is divided into the following parts:
 
-- [Mbed TLS full documentation](https://tls.mbed.org/).
-- [Platform Security Architecture (PSA)](https://developer.arm.com/products/architecture/security-architectures/platform-security-architecture).
-- [Mbed uVisor full documentation](https://docs.mbed.com/docs/uvisor-and-uvisor-lib-documentation/en/latest/).
+- Mbed TLS. For details, please see our [full documentation](https://tls.mbed.org/).
+- Platform Security Architecture (PSA). For details, please see our [full documentation](https://developer.arm.com/products/architecture/security-architectures/platform-security-architecture).
+- Mbed uVisor. For details, please see our [full documentation](https://docs.mbed.com/docs/uvisor-and-uvisor-lib-documentation/en/latest/).
 
 <span class="warnings">**Warning**: uVisor is superseded by the Secure Partition Manager (SPM) defined in the ARM Platform Security Architecture (PSA). uVisor is deprecated as of Mbed OS 5.10, and being replaced by a native PSA-compliant implementation of SPM.</span>
 
-For working with these modules in Mbed OS context refer to the following links:
+For information about working with these modules in Mbed OS context, please refer to the following documents:
 
 - [Connection security through Arm Mbed TLS](/docs/development/reference/tls.html).
-- Platform Security Architecture - TBD - under development
+- Platform Security Architecture - TBD - under development.
 - [Device security through Arm Mbed uVisor](/docs/development/reference/uvisor.html).