change broken pipe errors to a warning

as there are legitimate times when piping several commands that a broken pipe "error" arises even though the commands work as expected - e.g.

`qsv slice data100.csv | qsv slice --length 1`

where the first slice is still streaming to the second slice and the second slice finishes "early" after getting just one record

We have a Warning instead of an Abort exitcode and still send a message to stderr.

cc @rzmk

src/clitypes.rs

@@ -131,7 +131,7 @@ pub enum QsvExitCode {
     NetworkError   = 3,
     OutOfMemory    = 4,
     EncodingError  = 5,
-    Abort          = 255,
+    Warning        = 255,
 }
 
 impl Termination for QsvExitCode {

src/main.rs

@@ -282,9 +282,9 @@ sponsored by datHere - Data Infrastructure Engineering (https://qsv.datHere.com)
                 QsvExitCode::Bad
             },
             Err(CliError::Io(ref err)) if err.kind() == io::ErrorKind::BrokenPipe => {
-                werr!("broken pipe error: {err}");
+                wwarn!("broken pipe warning");
                 util::log_end(qsv_args, now);
-                QsvExitCode::Abort
+                QsvExitCode::Warning
             },
             Err(CliError::Io(err)) => {
                 werr!("io error: {err}");

src/maindp.rs

@@ -198,9 +198,9 @@ Please choose one of the following commands:",
                 QsvExitCode::Bad
             },
             Err(CliError::Io(ref err)) if err.kind() == io::ErrorKind::BrokenPipe => {
-                werr!("broken pipe error: {err}");
+                wwarn!("broken pipe warning");
                 util::log_end(qsv_args, now);
-                QsvExitCode::Abort
+                QsvExitCode::Warning
             },
             Err(CliError::Io(err)) => {
                 werr!("io error: {err}");

src/mainlite.rs

@@ -185,9 +185,9 @@ Please choose one of the following commands:",
                 QsvExitCode::Bad
             },
             Err(CliError::Io(ref err)) if err.kind() == io::ErrorKind::BrokenPipe => {
-                werr!("broken pipe error: {err}");
+                wwarn!("broken pipe warning");
                 util::log_end(qsv_args, now);
-                QsvExitCode::Abort
+                QsvExitCode::Warning
             },
             Err(CliError::Io(err)) => {
                 werr!("io error: {err}");