nushell: Crash while typing

Describe the bug panic while typing

To Reproduce Steps to reproduce the behavior:

1. type alias fg_blue = echo $(ansi -e '34m')
2. type fg_blue and watch the crash as you type the e

Expected behavior not crash

Screenshots

01/13/2021 09:48:39.976 AM ¯\_(ツ)_/¯ ▶ alias fg_blue = echo $(ansi -e '34m')
01/13/2021 09:48:41.743 AM ¯\_(ツ)_/¯ ▶ fg_bluthread 'main' panicked at 'index out of bounds: the len is 7 but the index is 7', crates\nu-engine\src\shell\painter.rs:49:13
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace

[process exited with code 101]

Configuration (please complete the following information):

Run version | pivot and paste the output to show OS, features, etc.

key	value
version	0.25.2
branch	main
short_commit	d06f457b
commit_hash	‘d06f457b2a7dee3acc71ecd0dc8b6a34afbfc5d8’
commit_date	2021-01-11 22:59:53
build_os	windows-x86_64
rust_version	rustc 1.49.0 (e1884a8e3 2020-12-29)
rust_channel	stable (default)
cargo_version	cargo 1.49.0 (d00d64df9 2020-12-05)
pkg_version	0.25.2
build_time	2021-01-12 07:29:22
build_rust_channel	release
features	clipboard-cli, ctrlc, default, directories, dirs, git, ichwh, ptree, rich-benchmark, rustyline, term, trash, uuid, which, zip