Rename/deprecate range to slice (#14825)

# Description
As the `range` command has an ambiguous name (does it construct a range
type?, does it iterate a range like `seq`) replace it with a more
descriptive verb of what it does: `slice`

Closes #14130
# User-Facing Changes
`range` is now deprecated and replaced in whole by `slice` with the same
behavior.
`range` will be removed in `0.103.0`

# Tests + Formatting
Tests have been updated to use `slice`

# After submitting

- [ ] prepare PR for `nu_scripts` (several usages of `range` to be
fixed)
- [ ] update documentation usages of `range` after release

tests/repl/test_engine.rs

@@ -441,7 +441,7 @@ fn better_operator_spans() -> TestResult {
 
 #[test]
 fn range_right_exclusive() -> TestResult {
-    run_test(r#"[1, 4, 5, 8, 9] | range 1..<3 | math sum"#, "9")
+    run_test(r#"[1, 4, 5, 8, 9] | slice 1..<3 | math sum"#, "9")
 }
 
 /// Issue #7872