plugins/gx: init

Strip `lib` from `lib.types.`

Co-authored-by: Gaétan Lepage <33058747+GaetanLepage@users.noreply.github.com>

Fix settingsExample expression

Co-authored-by: Matt Sturgeon <matt@sturgeon.me.uk>

Use '-version of options for better examples

Fix indentation in example lua code

Remove trailing space

Replace use of literalLua with strings

Revert to use literalLua

Use lib.mkDefault

Co-authored-by: Gaétan Lepage <33058747+GaetanLepage@users.noreply.github.com>

tests/test-sources/plugins/by-name/gx/default.nix

@@ -0,0 +1,64 @@
+{
+  empty = {
+    plugins.gx.enable = true;
+  };
+
+  default = {
+    plugins.gx = {
+      enable = true;
+
+      disableNetrwGx = true;
+
+      settings = {
+        open_browser_app = null;
+        open_browser_args = [ ];
+        handlers = { };
+        handler_options = {
+          search_engine = "google";
+          select_for_search = false;
+          git_remotes = [
+            "upstream"
+            "origin"
+          ];
+          git_remote_push = false;
+        };
+      };
+    };
+  };
+
+  example = {
+    plugins.gx = {
+      enable = true;
+
+      settings = {
+        handlers = {
+          rust = {
+            name = "rust";
+            filetype = [ "toml" ];
+            filename = "Cargo.toml";
+            handle.__raw = ''
+              function(mode, line, _)
+                local crate = require("gx.helper").find(line, mode, "(%w+)%s-=%s")
+
+                if crate then
+                  return "https://crates.io/crates/" .. crate
+                end
+              end
+            '';
+          };
+        };
+        handler_options = {
+          search_engine = "duckduckgo";
+          git_remotes.__raw = ''
+            function(fname)
+              if fname:match("myproject") then
+                  return { "mygit" }
+              end
+              return { "upstream", "origin" }
+            end
+          '';
+        };
+      };
+    };
+  };
+}