Fix ncurses backspace key

Ncurses does some special handling for backspace, normally comparing it
to the KEY_BACKSPACE constant. However to make this work, the right
backspace escape sequence needs to be set in the terminfo.

XTerm has this set to ^H, but it always sends ^H. Since Alacritty
usually sends ^? instead, this needs to be specified to allow correct
interpretation for ncurses.

CHANGELOG.md

@@ -49,6 +49,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Text getting recognized as URLs without slashes separating the scheme
 - URL parser dropping trailing slashes from valid URLs
 - UTF-8 BOM skipped when reading config file
+- Terminfo backspace escape sequence (`kbs`)
 
 ### Removed
 

extra/alacritty.info

@@ -52,7 +52,7 @@ alacritty+common|base fragment for alacritty,
     sgr0=\E(B\E[m, smacs=\E(0, smam=\E[?7h, smir=\E[4h,
     smkx=\E[?1h\E=, smm=\E[?1034h, smso=\E[7m, smul=\E[4m,
     tbc=\E[3g, vpa=\E[%i%p1%dd, E3=\E[3J,
-    kbs=^H,
+    kbs=^?,
     ritm=\E[23m, sitm=\E[3m,
     mc5i,
     mc0=\E[i, mc4=\E[4i, mc5=\E[5i,