Add and Fix docs for split_unescape

[ajratnam]

split_unescape function didn't have its docstring completly written. The example in the doc had a mistake, raw strings also cannot end with a single backslash.

[fliiiix]

Do you have any idea why

>>> split_unescape(r'foo\|bar', '|')
['foo|bar']

leads to radish/utils.py:190: DeprecationWarning: invalid escape sequence |

because i think that should not happen because we us a raw string

[codecov[bot]]

Codecov Report

All modified lines are covered by tests :white_check_mark:

Comparison is base (a515e15) 87.26% compared to head (46580cc) 87.26%.

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[ajratnam]

I think that's because you normally use r strings to unescape any escaped sequence but in our case \| isn't an escape sequence so nothing is being escaped

>>> r'\|' == '\|'
True
>>> print(r'\|')
\|
>>> print('\|')
\|

imo, the fix for it would be using normal string with \\ or I think it maybe some issue with flake8 also

[ajratnam]

Yeah, I changed it to that, and my linter doesn't show me that error anymore. I think this fixes #443

[fliiiix]

thanks again merged and release with 0.17.0