chore: rewrite user-facing messages in Setup module

Conservative cleanup of frappe.throw/msgprint messages per the message style
guide; meaning, severity, and .format() arguments are unchanged:

- index bare {} placeholders as {0}/{1}/... so translators can reorder
- move f-strings / .format() / concatenation out of _() (they break gettext
  extraction and never translate)
- wrap translatable dynamic values (DocType/Select labels) in _()
- fix grammar and colloquialisms
- drop no-op _() wrapping runtime-built strings

Part of #53976.

erpnext/setup/doctype/item_group/item_group.py

@@ -46,7 +46,9 @@ class ItemGroup(NestedSet):
 					frappe.throw(
 						_("{0} entered twice {1} in Item Taxes").format(
 							frappe.bold(d.item_tax_template),
-							f"for tax category {frappe.bold(d.tax_category)}" if d.tax_category else "",
+							_("for tax category {0}").format(frappe.bold(d.tax_category))
+							if d.tax_category
+							else "",
 						)
 					)
 				else:

erpnext/setup/doctype/transaction_deletion_record/transaction_deletion_record.py

@@ -646,7 +646,7 @@ class TransactionDeletionRecord(Document):
 	def validate_doc_status(self):
 		if self.status != "Running":
 			frappe.throw(
-				_("{0} is not running. Cannot trigger events for this Document").format(
+				_("{0} is not running. Cannot trigger events for this document").format(
 					get_link_to_form("Transaction Deletion Record", self.name)
 				)
 			)

erpnext/setup/setup_wizard/operations/taxes_setup.py

@@ -11,7 +11,7 @@ from frappe import _
 
 def setup_taxes_and_charges(company_name: str, country: str):
 	if not frappe.db.exists("Company", company_name):
-		frappe.throw(_("Company {} does not exist yet. Taxes setup aborted.").format(company_name))
+		frappe.throw(_("Company {0} does not exist yet. Taxes setup aborted.").format(company_name))
 
 	file_path = os.path.join(os.path.dirname(__file__), "..", "data", "country_wise_tax.json")
 	with open(file_path) as json_file: