Vendor selectionhighlight, bracketmatch, colorpreview, navigate, editorconfig (2.1.8-7)

Five more plugins from lite-xl-plugins @ 31eef29, all default VSCode
behaviors:

- selectionhighlight: highlights other occurrences of the selected word
- bracketmatch: highlights the bracket matching the one under the cursor
- colorpreview: inline swatches for #hex/rgb()/hsl() color literals
- navigate: Go Back / Go Forward cursor history (alt+left/right)
- editorconfig: applies .editorconfig files; vendored as the whole
  upstream directory (parser + test harness, lite-xl test editorconfig);
  builds on the bundled trimwhitespace plugin

All depend on core only (editorconfig additionally on trimwhitespace,
already shipped). Verified against the built package: all plugins load,
navigate registers its commands, and an .editorconfig with
indent_size = 2 is applied to an opened file.

Pinned to lite-xl-plugins @ 31eef29 (see debian/extra/README.source).

debian/extra/plugins/editorconfig/tests/glob/brackets.in

@@ -0,0 +1,51 @@
+; test [ and ]
+
+root=true
+
+; Character choice
+[[ab].a]
+choice=true
+
+; Negative character choice
+[[!ab].b]
+choice=false
+
+; Character range
+[[d-g].c]
+range=true
+
+; Negative character range
+[[!d-g].d]
+range=false
+
+; Range and choice
+[[abd-g].e]
+range_and_choice=true
+
+; Choice with dash
+[[-ab].f]
+choice_with_dash=true
+
+; Close bracket inside
+[[\]ab].g]
+close_inside=true
+
+; Close bracket outside
+[[ab]].g]
+close_outside=true
+
+; Negative close bracket inside
+[[!\]ab].g]
+close_inside=false
+
+; Negative¬close bracket outside
+[[!ab]].g]
+close_outside=false
+
+; Slash inside brackets
+[ab[e/]cd.i]
+slash_inside=true
+
+; Slash after an half-open bracket
+[ab[/c]
+slash_half_open=true