fix(bt/bluedroid): correct the readme links for BLE periodic examples

Author: esp-cjh

examples/bluetooth/bluedroid/ble_50/ble50_security_client/tutorial/ble50_security_client_Example_Walkthrough.md

@@ -7,7 +7,7 @@
 * The peripheral device is normally a GATT Server that exposes Services and Characteristics. The peripheral replies with a *Aux Connect Pairing Response* followed by authentication and exchange of keys. If the bonding process is also executed, the Long Term Keys are stored for subsequent connections. Finally an encrypted channel is established which can support protection against Man-In-The-Middle (MITM) attacks depending on the security configuration. 
 * The code is implemented using an Application Profile that upon registration, allows to set the local privacy configuration as events are triggered during the life time of the program. 
 
-This document only includes a description of the security aspects of the BLE5.0 Security GATT Client implementation, for the more infor about extended scan , periodic scan please refer to [Periodic_Sync_Example Walkthrough] (../../peroidic_sync/tutorial/Periodic_Sync_Example_Walkthrough.md).
+This document only includes a description of the security aspects of the BLE5.0 Security GATT Client implementation, for the more info about extended scan , periodic scan please refer to [Periodic_Sync_Example Walkthrough] (../../periodic_sync/tutorial/Periodic_Sync_Example_Walkthrough.md).
 
 ##include
 
@@ -144,4 +144,4 @@ case ESP_GAP_BLE_AUTH_CMPL_EVT: {
 
 ## Conclusion
 
-In this document, a review of the security aspects of the BLE5.0 GATT Client has been realized. BLE security encompasses Pairing, Bonding and Encryption. In order to establish a secure link between a central and a peripheral device, the local privacy of the GATT client is set, which allows the BLE stack to set necessary security parameters automatically without the need of additional user configuration. The combination of features and capabilities of the peer devices results in the selection of the appropriate pairing method which the BLE stack then executes. Immediately, the required keys are generated and exchanged and the encryption of subsequent messages is started using the AES-128 engine. These steps trigger different events that are managed by the GATT and GAP event handlers which can be used to print useful information such as the types of keys exchanged and the pairing status. The rest of the security GATT client functionality such as registering for notifications of characteristics is implemented in the same way as in [Periodic Sync Example Walkthrough](../../peroidic_sync/tutorial/Periodic_Sync_Example_Walkthrough.md).
+In this document, a review of the security aspects of the BLE5.0 GATT Client has been realized. BLE security encompasses Pairing, Bonding and Encryption. In order to establish a secure link between a central and a peripheral device, the local privacy of the GATT client is set, which allows the BLE stack to set necessary security parameters automatically without the need of additional user configuration. The combination of features and capabilities of the peer devices results in the selection of the appropriate pairing method which the BLE stack then executes. Immediately, the required keys are generated and exchanged and the encryption of subsequent messages is started using the AES-128 engine. These steps trigger different events that are managed by the GATT and GAP event handlers which can be used to print useful information such as the types of keys exchanged and the pairing status. The rest of the security GATT client functionality such as registering for notifications of characteristics is implemented in the same way as in [Periodic Sync Example Walkthrough](../../periodic_sync/tutorial/Periodic_Sync_Example_Walkthrough.md).

examples/bluetooth/bluedroid/ble_50/periodic_adv/README.md

@@ -6,7 +6,7 @@
 This example support for the periodic advertisement which allow the scanner to sync with the advertiser so that scanner and advertiser wake up same time. It support extended adv with 2M phy in connectable mode.
 
 
-To test this demo, we can run the [periodic_sync_demo](../peroidic_sync), which can do periodic scan and try to sync with periodic adv.
+To test this demo, we can run the [periodic_sync_demo](../periodic_sync), which can do periodic scan and try to sync with periodic adv.
 
 
 Please, check this [tutorial](tutorial/Periodic_adv_Example_Walkthrough.md) for more information about this example.

examples/bluetooth/bluedroid/ble_50/periodic_sync/README.md

@@ -5,7 +5,7 @@
 
 This example supports the periodic extended scan to scan the extended advertisement.
 
-To test this demo, we can run the [periodic_adv_demo](../peroidic_adv), which can start extended advertisement with supported param.
+To test this demo, we can run the [periodic_adv_demo](../periodic_adv), which can start extended advertisement with supported param.
 
 Please, check this [tutorial](tutorial/Periodic_Sync_Example_Walkthrough.md) for more information about this example.