Dedupe forward class declarations.

Scripts/precommit.py

@@ -171,6 +171,7 @@ def sort_include_block(text, filepath, filename, file_extension):
 def sort_class_statement_block(text, filepath, filename, file_extension):
     lines = text.split('\n')
     lines = [line.strip() for line in lines if line.strip()]
+    lines = list(set(lines))
     lines.sort()
     return '\n' + '\n'.join(lines) + '\n'
 

Signal/src/ViewControllers/ConversationView/Cells/ConversationViewCell.h

@@ -15,12 +15,10 @@ NS_ASSUME_NONNULL_BEGIN
 @class TSErrorMessage;
 @class TSInteraction;
 @class TSInvalidIdentityKeyErrorMessage;
-@class TSInvalidIdentityKeyErrorMessage;
 @class TSMessage;
 @class TSOutgoingMessage;
 @class TSQuotedMessage;
 @class YapDatabaseReadTransaction;
-@class YapDatabaseReadTransaction;
 
 @protocol ConversationViewCellDelegate <NSObject>