Merge bitcoin-core/gui#771: Avoid error-prone leading whitespace in translatable strings

856325fac1 lint: Add `lint-qt-translation.py` (Hennadii Stepanov)
294a018bf5 qt: Avoid error prone leading spaces in translatable strings (Hennadii Stepanov)
d8298e7f06 qt, refactor: Drop superfluous type conversions (Hennadii Stepanov)

Pull request description:

  While working on the GUI translation via Transifex web interface, I found it error-prone to have leading whitespace in translatable strings. This is because it is very easy to unintentionally drop them in translations unnoticed.

  Fixed all current cases. Added a linter to prevent similar cases in the future.

ACKs for top commit:
  furszy:
    utACK 856325f

Tree-SHA512: b1ca5effb2db6649e1e99382de79acf3a9f81cc9dad434db5623338489e597897e8addd60c1ab3dcc7506ae62753a7a4ad5a41d7a865f8fcdf94348b54baa7e7

test/lint/lint-qt-translation.py

@@ -0,0 +1,23 @@
+#!/usr/bin/env python3
+#
+# Copyright (c) 2023-present The Bitcoin Core developers
+# Distributed under the MIT software license, see the accompanying
+# file COPYING or https://opensource.org/license/mit/.
+#
+# Check for leading whitespaces in the translatable strings.
+
+import subprocess
+import sys
+
+
+def main():
+    tr_strings = subprocess.run(['git', 'grep', '-e', 'tr("[[:space:]]', '--', 'src/qt'], stdout=subprocess.PIPE, text=True).stdout
+
+    if tr_strings.strip():
+        print("Avoid leading whitespaces in:")
+        print(tr_strings)
+        sys.exit(1)
+
+
+if __name__ == "__main__":
+    main()