[PATCH 4/5] SubmittingPatches: remove confusing guidance about base branches

From: Linus Arver <linusa@google.com>

The guidance to "base your work on the oldest branch that your change is relevant to" was added in d0c26f0f56 (SubmittingPatches: Add new section about what to base work on, 2010-04-19). That commit also added the bullet points which describe the scenarios where one would use one of "maint", "master", "next", and "seen" ("pu" in the original as that was the name of this branch before it was renamed, per 828197de8f (docs: adjust for the recent rename of `pu` to `seen`, 2020-06-25)).

The underlying principle of this guidance was probably something like "base your work on the earlier-in-history branch so your change can be merged forward". However, this principle is already concretely explained in the accompanying bullet points. This principle should only come into play if none of the scenarios described in the bullet points apply --- and such a situation would be exceedingly rare.

Also, the guidance's wording of using the "oldest" branch is confusing when read together with the rest of this section, because three of the four named branches discussed ("master", "next", and "seen") move frequently enough to not be considered "old" at all.

For these reasons, remove the guidance _without_ preserving the meaning of the underlying principle, and instead add an overview of the four named branches.

Helped-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Linus Arver <linusa@google.com>
---
 Documentation/SubmittingPatches | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)