DOC: assorted typo fixes in the documentation

This is the third round of cleanups in various docs
diff --git a/doc/internals/entities-v2.txt b/doc/internals/entities-v2.txt
index 38d633d..86782c3 100644
--- a/doc/internals/entities-v2.txt
+++ b/doc/internals/entities-v2.txt
@@ -116,7 +116,7 @@
   - HH_ACCEPT_PROXY (waits for PROXY line and parses it)
   - HH_TCP_RULES (processes TCP rules)
   - HH_SSL_HS (starts SSL handshake)
-  - HH_ACCEPT_SESSION (instanciates a session)
+  - HH_ACCEPT_SESSION (instantiates a session)
 
 Identified handshake handlers for outgoing connections :
   - HH_SEND_PROXY (tries to build and send the PROXY line)