[spp] [PATCH v2 0/1] add bug report chapter

[Yasufumi Ogawa]

> From: Hideyuki Yamashita <yamashita.hideyuki at ntt-tx.co.jp>
> 
> v2:
> * remove unnecessary white space, modify typos.
> 
> Hideyuki Yamashita (1):
>    docs: add bug report chapter
Applied, thanks!

> 
>   CONTRIBUTING.txt           |  7 +++++++
>   docs/guides/bug_report.rst | 16 ++++++++++++++++
>   docs/guides/index.rst      |  1 +
>   3 files changed, 24 insertions(+)
>   create mode 100644 docs/guides/bug_report.rst
>