Fix escaping in PHP class references

docs/reference/method/MongoDBClient-listDatabases.txt

@@ -31,8 +31,8 @@ Definition
 
    :returns:
 
-      A traversable :phpclass:`MongoDB\\Model\DatabaseInfoIterator`, which
-      contains an :phpclass:`MongoDB\\Model\DatabaseInfo` object for each
+      A traversable :phpclass:`MongoDB\\Model\\DatabaseInfoIterator`, which
+      contains an :phpclass:`MongoDB\\Model\\DatabaseInfo` object for each
       database on the server.
 
 Example

docs/reference/method/MongoDBCollection-listIndexes.txt

@@ -31,9 +31,9 @@ Definition
 
    :returns:
 
-      A traversable :phpclass:`MongoDB\\Model\IndexInfoIterator`, which
-      contains an :phpclass:`MongoDB\\Model\IndexInfo` object for each index for
-      the collection.
+      A traversable :phpclass:`MongoDB\\Model\\IndexInfoIterator`, which
+      contains an :phpclass:`MongoDB\\Model\\IndexInfo` object for each index
+      for the collection.
 
 Example
 -------

docs/reference/method/MongoDBDatabase-listCollections.txt

@@ -31,8 +31,8 @@ Definition
 
    :returns:
 
-      A traversable :phpclass:`MongoDB\\Model\CollectionInfoIterator`, which
-      contains an :phpclass:`MongoDB\\Model\CollectionInfo` object for each
+      A traversable :phpclass:`MongoDB\\Model\\CollectionInfoIterator`, which
+      contains an :phpclass:`MongoDB\\Model\\CollectionInfo` object for each
       collection in the database.
 
 Example