Add -h as an additional help flag (#73)

* Explicitly added --help/-h flag to global flags. Moved global flags to a seperate help group.

* Removed --help/-h flag from displayed global flag list due to redundancy.

Author: Nadegamra

package.json

@@ -72,7 +72,8 @@
       "hello": {
         "description": "Say hello to the world and others"
       }
-    }
+    },
+    "additionalHelpFlags": ["-h"]
   },
   "repository": "iTwin/itwin-cli",
   "scripts": {

src/extensions/base-command.ts

@@ -26,6 +26,7 @@ export default abstract class BaseCommand extends Command {
     json: Flags.boolean({
       char: 'j',
       description: 'Pretty format the JSON command response and suppress all logging.',
+      helpGroup: 'GLOBAL',
       required: false
     }),
     silent: Flags.boolean({
@@ -37,6 +38,7 @@ export default abstract class BaseCommand extends Command {
     table: Flags.boolean({
       char: 't',
       description: 'Output the command response in a human-readable table format.',
+      helpGroup: 'GLOBAL',
       required: false
     }),
   }