vscode: improve tab size and wrapping

vscode: improve tab size and wrapping

The contrib/vscode/init.sh script initializes the .vscode directory with
some helpful metadata so VS Code handles Git code better.

One big issue that VS Code has is detecting the tab width based on file
type. ".txt" files were not covered by this script before, so add them
with the appropriate tab widths. This prevents inserting spaces instead
of tabs and keeps the tab width to eight instead of four or two.

While we are here, remove the "editor.wordWrap" settings. The editor's
word wrap is only cosmetic: it does not actually insert newlines when
your typing goes over the column limit. This can make it appear like you
have properly wrapped code, but it is incorrect. Further, existing code
that is over the column limit is wrapped even if your editor window is
wider than the limit. This can make reading such code more difficult.
Without these lines, VS Code renders the lines accurately, without
"ghost" newlines.

Signed-off-by: Derrick Stolee <derrickstolee@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>