Remove add_reaction for onReactionAdded in docs (#579)

Seems like it was leftover from some other function, probably one to handle both Added and Removed :)

.bumpversion.cfg

@@ -1,5 +1,5 @@
 [bumpversion]
-current_version = 1.9.6
+current_version = 1.9.7
 commit = True
 tag = True
 

examples/fetch.py

@@ -67,5 +67,5 @@ print("thread's type: {}".format(thread.type))
 
 # Print image url for 20 last images from thread.
 images = client.fetchThreadImages("<thread id>")
-for image in islice(image, 20):
+for image in islice(images, 20):
     print(image.large_preview_url)

fbchat/__init__.py

@@ -13,7 +13,7 @@ from ._client import Client
 from ._util import log  # TODO: Remove this (from examples too)
 
 __title__ = "fbchat"
-__version__ = "1.9.6"
+__version__ = "1.9.7"
 __description__ = "Facebook Chat (Messenger) for Python"
 
 __copyright__ = "Copyright 2015 - 2019 by Taehoon Kim"

fbchat/_client.py

@@ -3431,7 +3431,6 @@ class Client(object):
         Args:
             mid: Message ID, that user reacted to
             reaction (MessageReaction): Reaction
-            add_reaction: Whether user added or removed reaction
             author_id: The ID of the person who reacted to the message
             thread_id: Thread ID that the action was sent to. See :ref:`intro_threads`
             thread_type (ThreadType): Type of thread that the action was sent to. See :ref:`intro_threads`

fbchat/_state.py

@@ -27,6 +27,8 @@ def find_input_fields(html):
 def session_factory(user_agent=None):
     session = requests.session()
     session.headers["Referer"] = "https://www.facebook.com"
+    session.headers["Accept"] = "text/html"
+
     # TODO: Deprecate setting the user agent manually
     session.headers["User-Agent"] = user_agent or random.choice(_util.USER_AGENTS)
     return session