Fix several minor typos (#1603)

telethon/client/auth.py

@@ -92,7 +92,7 @@ class AuthMethods:
                 # Starting as a bot account
                 await client.start(bot_token=bot_token)
 
-                # Starting as an user account
+                # Starting as a user account
                 await client.start(phone)
                 # Please enter the code you received: 12345
                 # Please enter your password: *******

telethon/client/messages.py

@@ -406,7 +406,7 @@ class MessageMethods:
 
             from_user (`entity`):
                 Only messages from this user will be returned.
-                This parameter will be ignored if it is not an user.
+                This parameter will be ignored if it is not a user.
 
             wait_time (`int`):
                 Wait time (in seconds) between different

telethon/extensions/__init__.py

@@ -1,6 +1,6 @@
 """
 Several extensions Python is missing, such as a proper class to handle a TCP
-communication with support for cancelling the operation, and an utility class
+communication with support for cancelling the operation, and a utility class
 to read arbitrary binary data in a more comfortable way, with int/strings/etc.
 """
 from .binaryreader import BinaryReader

telethon/utils.py

@@ -1072,7 +1072,7 @@ def _rle_encode(string):
 
 def _decode_telegram_base64(string):
     """
-    Decodes an url-safe base64-encoded string into its bytes
+    Decodes a url-safe base64-encoded string into its bytes
     by first adding the stripped necessary padding characters.
 
     This is the way Telegram shares binary data as strings,