crecord: avoid duplicating lines when reverting noeol->eol change When reversing a patch that looks like this while using crecord: ``` @@ -301,4 +302,4 @@ zza zzb zzc zzd -zze \ No newline at end of file +zze ``` we would previously reverse the `-zze` line to be an add, encounter the "no newline" line and stop inspecting lines. This caused us to duplicate the line, producing `zzezze` (still without a newline). `break` is the correct action if we know there will be no lines afterwards, as would be the case in an eol -> noeol transition. It is incorrect if there are lines afterward, such as if both sides are missing the newline or if only the lhs is missing the newline. Differential Revision: https://phab.mercurial-scm.org/D12441