[InterNetNews/inn] e9a51c: Improve documentation of an overview rebuild

[Julien ÉLIE]

  Branch: refs/heads/2.7
  Home:   https://github.com/InterNetNews/inn
  Commit: e9a51c6dc460008d7aec850746357c18efce43c8
      https://github.com/InterNetNews/inn/commit/e9a51c6dc460008d7aec850746357c18efce43c8
  Author: Julien ÉLIE <Julien-Elie at users.noreply.github.com>
  Date:   2022-11-18 (Fri, 18 Nov 2022)

  Changed paths:
    M doc/pod/makehistory.pod

  Log Message:
  -----------
  Improve documentation of an overview rebuild

Mention the buffindexed buffers to create (when using that method) and the
fact that there may be error logs during the rebuild for articles whose
generated overview data exceed the internal limit in size of makehistory
(using QIO).