Qualified imports of pkg/testutil outnumber unqualified (55 to 7). Improve
consistency, and clarity, by changing the dot (unqualified) imports of
that package symbols to qualified.
This was extracted from https://github.com/elves/elvish/pull/1326. It
augments that change by honoring $E:PATHEXT and some other
minor improvements. This matches the behavior of the Go stdlib
os/exec.LookPath() function that is used to decide if what has been typed
(in a non-completion context) represents an external command.
The Elvish daemon should not inherit file descriptors open on the tty.
Make the daemon's stdin open on the null device and its stdout/stderr
open on a predictable file.
Fixes#1191
There are some Navigation mode corner cases whose current behavior is
surprising. Such as inserting a space before the filename when the space
isn't wanted or redundant. Also, selecting an empty directory and pressing
Enter should insert nothing rather than an empty string.
Fixes#1169