bugfix: lib/sh/util.sh: command(): updated $errors_only var name to $explicit_errors_only

lib/sh/util.sh: $explicit_errors_only: noted that verbosity=0 displays everything that isn't explicitly hidden

lib/sh/local.sh: psql(): use new stderr_is_errors=1 since psql's logging output comes on stdout, so stderr contains only errors. (the caveat of this is that the query output is normally mixed with logging info on stdout, and needs to be separated out to a different file descriptor using --output.)

lib/sh/util.sh: added $explicit_errors_only env var which shows only explicitly-displayed errors (those which have been redirected to fd 22). note that most of the time, this has the same effect as `verbosity=0 script...`.

lib/sh/util.sh: command(): support ensuring errors are visible by redirecting them to fd 22 (global stderr) when $stderr_is_errors is set

lib/sh/util.sh: `command`: always prepend -- to the args list (to ensure that the command name is not interpreted as a `command` option), not just when the command alias is used

lib/sh/util.sh: set_global_fds(): increase the log_level so the shadow_fd()/set_fd() function names aren't output at the default verbosity (3), and the redirection commands themselves aren't output at verbosity <= 2. set_global_fds() happens at the beginning of every script that uses util.sh, and is fairly predictable, so it isn't necessary to always echo these commands.

lib/sh/local.sh: psql(): use new convention for command-specific alternate stdout

lib/sh/make.sh: inline_make: use new convention for command-specific alternate stdin

*{.sh,run}: removed extra space between function name and ()