minor: read from / write to stylistic nit

Author: epc

source/reference/glossary.txt

@@ -572,8 +572,8 @@ Glossary
       A property of a distributed system requiring that all members
       always reflect the latest changes to the system. In a database
       system, this means that any system that can provide data must
-      reflect the latest writes at all times. In MongoDB, reads to a
-      primary have :term:`strict consistency`; reads to secondary
+      reflect the latest writes at all times. In MongoDB, reads from a
+      primary have :term:`strict consistency`; reads from secondary
       members have :term:`eventual consistency`.
 
    write concern