completions should not appear on parameter names unless it's a method override

[DetachHead]

that variable name is completely unrelated. i don't think completions would ever be useful here except when overriding a method

[beauxq]

I think this could have some usefulness, but it could be improved from how it is now.

It can be useful with longer words, so we don't have to type the whole word. But with short examples of 4 or 6 letter words, it's not really useful.

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Another way that it could be improved would be to recognize words out of symbol names.
In this example, it would be better if it saw the underscore separating words:

So it should only auto-complete hjklcvb, not sndbmnd_hjklcvb.

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Like we saw in #655
It's not as useful if it's pulling words from other libraries (or stdlib).
It would be best if it only pulls words from the codebase we're working on.

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The auto-complete shouldn't change between lowercase and uppercase, especially when it would violate pep8.

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Some of these adjustments might be easier that others. It might be an overall imrovement to disable them completely if we can't get enough of the individual improvements.