Add git guide

[bettio]

A practical guide about how to make commits and PRs for this project.

These changes are made under both the "Apache 2.0" and the "GNU Lesser General
Public License 2.1 or later" license terms (dual license).

SPDX-License-Identifier: Apache-2.0 OR LGPL-2.1-or-later

[UncleGrumpy]

This looks very helpful, but we should also make sure it gets included in the published documentation by adding it to doc/CmakeLists.txt around here:

AtomVM/doc/CMakeLists.txt

Line 28 in 6f66fa4

file(COPY ${CMAKE_SOURCE_DIR}/C_CODING_STYLE.md DESTINATION ${CMAKE_CURRENT_BINARY_DIR}/src)

It will be good to have this published, then the other AtomVM.org repos can just add a link to it in their readme or contribution guidelines.

[pguyot]

AFAIK we don't make it optional

[pguyot]

We should automate these rules in CI (especially to catch when I am too verbose in titles)

[UncleGrumpy]

I had a similar thought. I also wonder about using a pull request template.

[pguyot]

Thread T-019c6ce1-156b-722d-bd0e-f6515169196d is not shared with you

I'm not sure we had first line of commit messages this wide.

[petermm]

commit-title-stats.sh

figured out I needed to filter out "Merge pull request #.."

Still suggest 50 char recommendation with a 72 hard limit..

Commit subject line length (characters) — last 12 months, excluding merge PRs

Contributor	Commits	P25	P50	P75	P90	P95	Max	>50	%>50
Paul Guyot	509	32	41	51	59	64	87	136	26.7%
Davide Bettio	248	38	45	53	61	67	72	84	33.9%
Winford	42	36	50	57	62	65	98	20	47.6%
Peter M	42	27	37	45	52	56	61	5	11.9%
Jakub Gonet	21	20	24	36	46	46	49	0	0.0%
TOP 5 TOTAL	862	33	43	52	60	64	98	245	28.4%

[pguyot]

Thank you. I agree with your point. We can transition to more git messaging discipline but we'll definitely need some help from an automated tool :-)