track reasons for not renaming as well
track reasons for not renaming as well

Summary: Adds other RenameClasses metrics, tracking reason WHY things weren't renamed: `num_cant_delete, num_cant_rename, num_cant_rename_annotations, num_cant_rename_untouchable, num_classes_in_scope, num_not_whitelisted`. Also, bake remark bolding into **num_renamed** name so it stands out. See stats bot comments on this diff to see how it looks.

Reviewed By: int3

Differential Revision: D3553136

fbshipit-source-id: 849546e985ad88e3c1d2bfbbc855fa1dfca1fc9d

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