`-e "i\\6IlzWb"` is failing when accepted by GNU

[sylvestre]

with our impl:

echo "qqGG3" |cargo run sed -e "i\\6IlzWb"
    Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.06s
     Running `target/debug/sedapp sed -e 'i\6IlzWb'`
sed: i\6IlzWb:1:2: error: extra characters after \ at the end of `i' command

With GNU:

echo "qqGG3" |sed -e "i\\6IlzWb"
6IlzWb
qqGG3

[dspinellis]

Further GNU sed examples:

# Backslash is optional
$ echo hi | sed 'athere'
hi
there
$

# Spaces preceding the text are ignored
$ echo hi | sed 'a there'
hi
there
$

# EOF after EOL
$ echo hi | sed $'a\n'
hi

$

# EOF after \
$ echo hi | sed $'a\\\n'
hi

$

# First \ doesn't result in escaped characters
$ echo hi | sed 'a\tom'
hi
tom
$

# Text can follow the initial \
# Character escapes are supported
# Invalid escapes result in the character
$ echo mankind | sed $'i\\>\\h\\elll\bo\\nto\\\nall\\a'
>hello
to
all
mankind

[dspinellis]

@sylvestre I fixed it:

$ echo "qqGG3" | target/debug/sedapp sed -e 'i\6IlzWb'
6IlzWb
qqGG3