Bracket matching

[dingfeli]

Issue #, if available:
https://issues.amazon.com/issues/ECLIPSE-286

Premise

This PR revamps the rendering logic for the suggestion text, using the change in #37 as foundation. It also enables bracket matching during typeahead.

Description of changes:

• Separates each line in the suggestion texts to be rendered individually. This simplifies the top level rendering logic in renderer listener.
• Disables auto closing of brackets (this also includes strings) during typehead. This is done to aid bracket matching by highlighting the corresponding closing brackets as user types over an open bracket. The auto closing brackets that should have been added as user buffer during the typeahead would then be added after the preview ends.
• An addition of a workbench listener to revert aforementioned settings back to what they were prior to workbench shutdown. This is done to prevent a persistent change of bracket related user settings should users quit eclipse while the preview is still active.

Apart from the features addition, there are also the following bug fixes:

• Fixes IDE induced caret "jumps" terminating preview prematurely.
• Fixes typeahead deadreckoning becoming out of sync when user backspaces more than one character at a time.
• Deduplicates partially typed suggestion when user accepts answer after having typed ahead.

Test

Closing brackets are being highlighted during typeahead:

Unresolved brackets are added to user buffer upon preview termination:

Disclaimer

There are still some edge cases that we would need to cover in the future with more changes.
Most of these have to do with the differences between how the lsp and the IDE interprets whitespace.

For example, consider the following text:

1. public static void main(String[] args) {
2.     int x = 1;
3. 
4.     int y = 2;
5. }

Currently is it possible that the user may not be able to typeahead across line 3. This is because the suggestion on from line 2 to line 3 may very well be \n or \n\t or \n or \n\n.
For reference, depending on the IDE's settings, when user types from line 2 to 3, the input as observed by verifyText is going to be either \n\t if they have tabs only enabled or \n ' ' ** $tabSize if they have space only enabled.

I have made an issue to track these: https://issues.amazon.com/issues/ECLIPSE-340

By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of your choice.

[breedloj]

This made me chuckle..but maybe NONE? 😄