`string-inflection-get-current-word` is not mode aware

When editing a python file like
```
fooBar-barFoo
         ^---- cursor position
```

and calling `string-inflection-python-style-cycle` the result is
```
foo_bar_bar_foo
```

and not the expected
```
fooBar-bar_foo
```

Probably the mode aware `(symbol-at-point)` function should be used to determine the current word.