docs: added docs for --force flag for zarf tools gen-key

updated the docs for the rest of the flags as well

Signed-off-by: Nicholas Rees <nicholas@reessoftware.com>

Author: nicholas-rees

site/src/content/docs/commands/zarf_tools_gen-key.md

@@ -17,10 +17,11 @@ zarf tools gen-key [flags]
 ### Options
 
 ```
-  -h, --help              help for gen-key
-      --interactive       Interactively prompt for registry server, username, and password if not provided
-      --password string   Password
-  -p, --password-stdin    Take the password from stdin
+      --force                       Force overwrite of keyfiles -- no effect when running interactive
+  -h, --help                        help for gen-key
+      --interactive                 Interactively prompt for password
+      --password string             Private key password -- no effect when running interactive (default "")
+      --password-stdin --password   Take the password from stdin -- overrides --password; no effect when running interactive
 ```
 
 ### Options inherited from parent commands