EnhancedTermTypedCharSupport: store queued chars in a deque

[codeofdusk]

Is your feature request related to a problem? Please describe.

Currently, the EnhancedTermTypedCharSupport class stores its queue of typed characters in a list. Per the Python docs:

Though list objects support similar operations, they are optimized for fast fixed-length operations and incur $\mathcal{O}(n)$ memory movement costs for pop(0) and insert(0, v) operations which change both the size and position of the underlying data representation.

Describe the solution you'd like

Use a deque instead. pop characters to be dispatched instead of iterating over the entire list and rebuilding it.

Describe alternatives you've considered

Keep the current implementation: the number of queued characters is small and time/space savings are theoretical.

[feerrenrut]

Before accepting a change like this I'd like to see it actually measured under standard and extreme conditions. IE prove that it doesn't make things worse. I agree, this should perform better, but good to know for sure it does in the cases that this code encounters.

[Adriani90]

@codeofdusk are you still thinking implementing this makes sense? Or is the poerformance much better now?
If you think it makes sense, could you provide test results in extreme situations?

[codeofdusk]

I have little confidence that a PR like this without obvious user benefit will be accepted, see #11484. It just doesn't meet the #11006 bar. If you'd like to provide benchmarks I'm happy to take this on.

[seanbudd]

@codeofdusk that issue is closed, we welcome positive code refactors that increase maintainability