hang on save when a comment_text filter uses 3 args

[AssemblerManiac]

I have added a filter for 'comment_text' based on the built in filter definition using 3 args. Your call to apply_filters in function get_comment_content, appx line 977, only sends two args to the function. This causes an internal server error on our IIS server (mismatched arg count basically).

I suggest adding a 3rd argument of an empty array (as defined in the base WP system) to solve the issue. Same issue applies to 'get_comment_text'. Any other addon that tries to use the 3rd arg will cause the same hang.

I've adjusted our code to only use 2 args, but thought you might like to know the cause of a hang problem.