Use configured shell from vscode.env.shell instead of process.env.SHELL

This will make sure the detection system will use the configured shell in VS Code,
and works without having on the SHELL environment variable set.

Author: rafaelfranca

vscode/src/ruby.ts

@@ -65,7 +65,6 @@ export class Ruby implements RubyInterface {
     .getConfiguration("rubyLsp")
     .get<ManagerConfiguration>("rubyVersionManager")!;
 
-  private readonly shell = process.env.SHELL?.replace(/(\s+)/g, "\\$1");
   private _env: NodeJS.ProcessEnv = {};
   private _error = false;
   private readonly context: vscode.ExtensionContext;
@@ -402,12 +401,8 @@ export class Ruby implements RubyInterface {
 
   private async toolExists(tool: string) {
     try {
-      let command = this.shell ? `${this.shell} -i -c '` : "";
-      command += `${tool} --version`;
-
-      if (this.shell) {
-        command += "'";
-      }
+      const shell = vscode.env.shell.replace(/(\s+)/g, "\\$1");
+      const command = `${shell} -i -c '${tool} --version'`;
 
       this.outputChannel.info(`Checking if ${tool} is available on the path with command: ${command}`);