Fix a few spelling errors

docs/spelling/technical.txt

@@ -1,4 +1,6 @@
 iterables
+iterable
+mimetype
 timestamp
 metadata
 spam
@@ -12,3 +14,4 @@ spritemap
 online
 inbox
 subclassing
+codebase

fbchat/_client.py

@@ -477,7 +477,7 @@ class Client:
 
         Args:
             threads: Threads to set as unread
-            at: Timestam to signal the read cursor at
+            at: Timestamp to signal the read cursor at
         """
         return self._read_status(False, threads, at)
 

fbchat/_thread.py

@@ -420,7 +420,7 @@ class ThreadABC(metaclass=abc.ABCMeta):
     def set_color(self, color: str):
         """Change thread color.
 
-        The new color must be one of the following:
+        The new color must be one of the following::
 
             "#0084ff", "#44bec7", "#ffc300", "#fa3c4c", "#d696bb", "#6699cc", "#13cf13",
             "#ff7e29", "#e68585", "#7646ff", "#20cef5", "#67b868", "#d4a88c", "#ff5ca1",