Unnecessary linebreak in slice notation after a multiline string literal

[maple3142]

Describe the style change

Current black format the slice notation just after a multiline string literal over multiple lines, but that's unnecessary when the line containing closing triple quote is short.

Examples in the current Black style

s = """
lorem ipsum dolor sit amet
consectetur adipiscing elit
sed do eiusmod tempor incididunt
ut labore et dolore magna aliqua
ut enim ad minim veniam
quis nostrud exercitation ullamco
laboris nisi ut aliquip ex ea commodo
consequat duis aute irure dolor in
reprehenderit in voluptate velit esse
cillum dolore eu fugiat nulla pariatur
excepteur sint occaecat cupidatat non
proident sunt in culpa qui officia
deserunt mollit anim id est laborum
"""[
    1:
]
print(s)

Desired style

s = """
lorem ipsum dolor sit amet
consectetur adipiscing elit
sed do eiusmod tempor incididunt
ut labore et dolore magna aliqua
ut enim ad minim veniam
quis nostrud exercitation ullamco
laboris nisi ut aliquip ex ea commodo
consequat duis aute irure dolor in
reprehenderit in voluptate velit esse
cillum dolore eu fugiat nulla pariatur
excepteur sint occaecat cupidatat non
proident sunt in culpa qui officia
deserunt mollit anim id est laborum
"""[1:]
print(s)

Additional context

[cobaltt7]

This issue is fixed in the currently unstable multiline_string_formatting style, togglable with --unstable or --preview --enable-unstable-feature multiline_string_formatting. It's still unstable due to it occasionally causing worse formatting, which is being tracked in #4159.