Add concise docstrings to each xxxCoder class describing their purpose.

aider/coders/editblock_coder.py

@@ -13,6 +13,7 @@ from .editblock_prompts import EditBlockPrompts
 
 
 class EditBlockCoder(Coder):
+    """A coder that uses edit blocks for code modifications."""
     edit_format = "diff"
     gpt_prompts = EditBlockPrompts()
 

aider/coders/editblock_fenced_coder.py

@@ -4,5 +4,6 @@ from .editblock_fenced_prompts import EditBlockFencedPrompts
 
 
 class EditBlockFencedCoder(EditBlockCoder):
+    """A coder that uses fenced edit blocks for code modifications."""
     edit_format = "diff-fenced"
     gpt_prompts = EditBlockFencedPrompts()

aider/coders/help_coder.py

@@ -4,6 +4,7 @@ from .help_prompts import HelpPrompts
 
 
 class HelpCoder(Coder):
+    """A coder that provides help and documentation."""
     edit_format = "help"
     gpt_prompts = HelpPrompts()
 

aider/coders/udiff_coder.py

@@ -44,6 +44,7 @@ other_hunks_applied = (
 
 
 class UnifiedDiffCoder(Coder):
+    """A coder that uses unified diff format for code modifications."""
     edit_format = "udiff"
     gpt_prompts = UnifiedDiffPrompts()
 

aider/coders/wholefile_coder.py

@@ -8,6 +8,7 @@ from .wholefile_prompts import WholeFilePrompts
 
 
 class WholeFileCoder(Coder):
+    """A coder that operates on entire files for code modifications."""
     edit_format = "whole"
     gpt_prompts = WholeFilePrompts()