Support redirect stderr and stdout+stderr with a pipe (#11708)

# Description
Close: #9673
Close: #8277
Close: #10944

This pr introduces the following syntax:
1. `e>|`, pipe stderr to next command. Example: `$env.FOO=bar nu
--testbin echo_env_stderr FOO e>| str length`
2. `o+e>|` and `e+o>|`, pipe both stdout and stderr to next command,
example: `$env.FOO=bar nu --testbin echo_env_mixed out-err FOO FOO e+o>|
str length`

Note: it only works for external commands. ~There is no different for
internal commands, that is, the following three commands do the same
things:~ Edit: it raises errors if we want to pipes for internal
commands
``` 
❯ ls e>| str length
Error:   × `e>|` only works with external streams
   ╭─[entry #1:1:1]
 1 │ ls e>| str length
   ·    ─┬─
   ·     ╰── `e>|` only works on external streams
   ╰────

❯ ls e+o>| str length
Error:   × `o+e>|` only works with external streams
   ╭─[entry #2:1:1]
 1 │ ls e+o>| str length
   ·    ──┬──
   ·      ╰── `o+e>|` only works on external streams
   ╰────
```

This can help us to avoid some strange issues like the following:

`$env.FOO=bar (nu --testbin echo_env_stderr FOO) e>| str length`

Which is hard to understand and hard to explain to users.

# User-Facing Changes
Nan

# Tests + Formatting
To be done

# After Submitting
Maybe update documentation about these syntax.

crates/nu-parser/src/lite_parser.rs

@@ -37,6 +37,12 @@ impl LiteCommand {
 #[derive(Debug)]
 pub enum LiteElement {
     Command(Option<Span>, LiteCommand),
+    // Similar to LiteElement::Command, except the previous command's output is stderr piped.
+    // e.g: `e>| cmd`
+    ErrPipedCommand(Option<Span>, LiteCommand),
+    // Similar to LiteElement::Command, except the previous command's output is stderr + stdout piped.
+    // e.g: `o+e>| cmd`
+    OutErrPipedCommand(Option<Span>, LiteCommand),
     // final field indicates if it's in append mode
     Redirection(Span, Redirection, LiteCommand, bool),
     // SeparateRedirection variant can only be generated by two different Redirection variant
@@ -272,7 +278,9 @@ pub fn lite_parse(tokens: &[Token]) -> (LiteBlock, Option<ParseError>) {
                 last_connector = token.contents;
                 last_connector_span = Some(token.span);
             }
-            TokenContents::Pipe => {
+            pipe_token @ (TokenContents::Pipe
+            | TokenContents::ErrGreaterPipe
+            | TokenContents::OutErrGreaterPipe) => {
                 if let Some(err) = push_command_to(
                     &mut curr_pipeline,
                     curr_command,
@@ -283,8 +291,8 @@ pub fn lite_parse(tokens: &[Token]) -> (LiteBlock, Option<ParseError>) {
                 }
 
                 curr_command = LiteCommand::new();
-                last_token = TokenContents::Pipe;
-                last_connector = TokenContents::Pipe;
+                last_token = *pipe_token;
+                last_connector = *pipe_token;
                 last_connector_span = Some(token.span);
             }
             TokenContents::Eol => {
@@ -429,7 +437,35 @@ fn push_command_to(
                     is_append_mode,
                 ))
             }
-            None => pipeline.push(LiteElement::Command(last_connector_span, command)),
+            None => {
+                if last_connector == TokenContents::ErrGreaterPipe {
+                    pipeline.push(LiteElement::ErrPipedCommand(last_connector_span, command))
+                } else if last_connector == TokenContents::OutErrGreaterPipe {
+                    // Don't allow o+e>| along with redirection.
+                    for cmd in &pipeline.commands {
+                        if matches!(
+                            cmd,
+                            LiteElement::Redirection { .. }
+                                | LiteElement::SameTargetRedirection { .. }
+                                | LiteElement::SeparateRedirection { .. }
+                        ) {
+                            return Some(ParseError::LabeledError(
+                                "`o+e>|` pipe is not allowed to use with redirection".into(),
+                                "try to use different type of pipe, or remove redirection".into(),
+                                last_connector_span
+                                    .expect("internal error: outerr pipe missing span information"),
+                            ));
+                        }
+                    }
+
+                    pipeline.push(LiteElement::OutErrPipedCommand(
+                        last_connector_span,
+                        command,
+                    ))
+                } else {
+                    pipeline.push(LiteElement::Command(last_connector_span, command))
+                }
+            }
         }
         None
     } else if get_redirection(last_connector).is_some() {