Fixes #1963. Only remove one character on backspace when wordwrap is on

[hippiehunter]

Fixes #1963 check if word wrap is enabled before removing the character from the model. If its enabled, use the wrap manager instead.

[tig]

Excellent find and fix. Thank you.

Once you fix the source formatting I'll merge.

[tig]

@hippiehunter, per @BDisp can you please also fix the Delete key use-case as part of this PR?

Many thanks for helping with this!

[BDisp]

@tig this bug is much more wide than this pr is intended for. Because now all the actions on the TextView unwrap and re-wrap, if word wrap is enabled, the management of the wrapped lines, like remove, add, is not needed anymore. So, this pr will not fix all the issues. Do you want I submit a pr to the @hippiehunter's repo or should I submit a new pr?

[BDisp]

@tig here is my fix https://github.com/BDisp/Terminal.Gui/tree/textview-word-wrap-delete-backwards-forwards-fix. @hippiehunter can merge into his pr or if you want I can create a new pr with my branch. Thanks.

[hippiehunter]

Is there anything else you need me to do on this PR?

[BDisp]

Is there anything else you need me to do on this PR?

For me, since you already merged my fix I think is all OK and I already approved. I appreciate your help for found this issue, but the fix implied more some changes. The management for remove and add runes on wrapped lines aren't need anymore and that why it was deleting twice when word wrap is enabled We must wait for @tig to merge or saying something. Thanks.