range operator accepts bot..=top as well as bot..top (#8382)

# Description

A compromise fix for #8162. Nushell range operator now accepts `..=` to
mean the range includes the top value, so you can use your Rust habits.
But the unadorned `..` range operator also includes the value, so you
can also use your Nushell habits.

_(Description of your pull request goes here. **Provide examples and/or
screenshots** if your changes affect the user experience.)_

```nushell
〉1..5
╭───┬───╮
│ 0 │ 1 │
│ 1 │ 2 │
│ 2 │ 3 │
│ 3 │ 4 │
│ 4 │ 5 │
╰───┴───╯
-------------------------------------------- /home/bobhy/src/rust/nushell --------------------------------------------
〉1..=5
╭───┬───╮
│ 0 │ 1 │
│ 1 │ 2 │
│ 2 │ 3 │
│ 3 │ 4 │
│ 4 │ 5 │
╰───┴───╯
-------------------------------------------- /home/bobhy/src/rust/nushell --------------------------------------------
〉1..<5
╭───┬───╮
│ 0 │ 1 │
│ 1 │ 2 │
│ 2 │ 3 │
│ 3 │ 4 │
╰───┴───╯
```
# User-Facing Changes

Existing scripts with range operator will continue to operate as
heretofore.

_(List of all changes that impact the user experience here. This helps
us keep track of breaking changes.)_

# Tests + Formatting

Don't forget to add tests that cover your changes.

Make sure you've run and fixed any issues with these commands:

- [x] `cargo fmt --all -- --check` to check standard code formatting
(`cargo fmt --all` applies these changes)
- [x] `cargo clippy --workspace -- -D warnings -D clippy::unwrap_used -A
clippy::needless_collect` to check that you're using the standard code
style
- [x] `cargo test --workspace` to check that all tests pass

# After Submitting

Will update the book to include new syntax.

crates/nu-parser/src/parser.rs

@@ -1500,7 +1500,7 @@ pub fn parse_range(
 
     // Range follows the following syntax: [<from>][<next_operator><next>]<range_operator>[<to>]
     //   where <next_operator> is ".."
-    //   and  <range_operator> is ".." or "..<"
+    //   and  <range_operator> is "..", "..=" or "..<"
     //   and one of the <from> or <to> bounds must be present (just '..' is not allowed since it
     //     looks like parent directory)
     //bugbug range cannot be [..] because that looks like parent directory
@@ -1553,12 +1553,12 @@ pub fn parse_range(
             return garbage(span);
         }
     } else {
-        let op_str = "..";
+        let op_str = if token.contains("..=") { "..=" } else { ".." };
         let op_span = Span::new(
             span.start + range_op_pos,
             span.start + range_op_pos + op_str.len(),
         );
-        (RangeInclusion::Inclusive, "..", op_span)
+        (RangeInclusion::Inclusive, op_str, op_span)
     };
 
     // Now, based on the operator positions, figure out where the bounds & next are located and
@@ -5178,7 +5178,12 @@ pub fn parse_expression(
 
         let split = name.splitn(2, |x| *x == b'=');
         let split: Vec<_> = split.collect();
-        if !name.starts_with(b"^") && split.len() == 2 && !split[0].is_empty() {
+        if !name.starts_with(b"^")
+            && split.len() == 2
+            && !split[0].is_empty()
+            && !split[0].ends_with(b"..")
+        // was range op ..=
+        {
             let point = split[0].len() + 1;
 
             let starting_error_count = working_set.parse_errors.len();