[PATCH v2 1/3] doc: provide guidance on user.name format

["brian m. carlson" <sandals@crustytoothpaste.net>]

It's a frequent misconception that the user.name variable controls
authentication in some way, and as a result, beginning users frequently
attempt to change it when they're having authentication troubles.
Document that the convention is that this variable represents some form
of a human's personal name, although that is not required.  In addition,
address concerns about whether Unicode is supported.

Use the term "personal name" as this is likely to draw the intended
contrast, be applicable across cultures which may have different naming
conventions, and be easily understandable to people who do not speak
English as their first language.  Indicate that "some form" is
conventionally used, as people may use a nickname or preferred name
instead of a full legal name.

Point users who may be confused about authentication to an appropriate
configuration option instead.

Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
---
 Documentation/git-commit-tree.txt | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/Documentation/git-commit-tree.txt b/Documentation/git-commit-tree.txt
index 4b90b9c12a..c794843634 100644
--- a/Documentation/git-commit-tree.txt
+++ b/Documentation/git-commit-tree.txt
@@ -92,6 +92,12 @@ if set:
 
 (nb "<", ">" and "\n"s are stripped)
 
+The author and committer names are by convention some form of a personal name,
+although Git does not enforce or require any particular form. Arbitrary Unicode
+may be used, subject to the constraints listed above. This name has no effect on
+authentication; for that, see the `credential.username` variable in
+linkgit::git-config[1].
+
 In case (some of) these environment variables are not set, the information
 is taken from the configuration items user.name and user.email, or, if not
 present, the environment variable EMAIL, or, if that is not set,