vscode: only overwrite C/C++ settings
The C/C++ settings are special, as they are the only generated VS Code
configurations that *will* change over the course of Git's development,
e.g. when a new constant is defined.
Therefore, let's only update the C/C++ settings, also to prevent user
modifications from being overwritten.
Ideally, we would keep user modifications in the C/C++ settings, but
that would require parsing JSON, a task for which a Unix shell script is
distinctly unsuited. So we write out .new files instead, and warn the
user if they may want to reconcile their changes.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>