Update descriptions

docs/guide/ecies.md

@@ -1,5 +1,5 @@
 title: ECIES
-description: Perform bulk encryption on data using a symmetric cipher and a random key.
+description: Uses ECIES symmetric key negotiation from public keys to encrypt arbitrarily long data streams.
 ---
 # ECIES
 

docs/guide/hierarchical.md

@@ -1,5 +1,5 @@
-title: HD Keys
+title: HDKeys
-description: Hierarichically derived keys support, let's you create and derive extended public and private keys.
+description: Lets you create and derive extended public and private keys according to the BIP32 standard for Hierarchical Deterministic (HD) keys.
 ---
 # HDKeys