docs: add a script to convert usage.rst to a man page

[skip ci]

docs/myrst2man.py

@@ -0,0 +1,67 @@
+#!/usr/bin/python3
+
+import time
+import locale
+import sys
+try:
+  locale.setlocale(locale.LC_ALL, '')
+except:
+  pass
+
+sys.path.insert(0, '..')
+import nvchecker
+
+from docutils.core import publish_cmdline, default_description
+from docutils import nodes
+from docutils.writers import manpage
+from docutils.parsers.rst import roles
+
+def ref_role(
+  role, rawtext, text, lineno, inliner,
+  options={}, content=[],
+):
+  node = nodes.reference(rawtext, text.title(), **options)
+  return [node], []
+
+def doc_role(
+  role, rawtext, text, lineno, inliner,
+  options={}, content=[],
+):
+  node = nodes.reference(rawtext, text, **options)
+  return [node], []
+
+roles.register_local_role('ref', ref_role)
+roles.register_local_role('doc', doc_role)
+
+class MyTranslator(manpage.Translator):
+  def visit_image(self, node):
+    raise nodes.SkipNode
+
+  def visit_topic(self, node):
+    self.body.append('\n')
+    raise nodes.SkipNode
+
+  def visit_title(self, node):
+    try:
+      super().visit_title(node)
+    except nodes.SkipNode:
+      if self.section_level == 0:
+        self._docinfo['title'] = 'nvchecker'
+        self._docinfo['subtitle'] = 'New version checker for software releases'
+        self._docinfo['title_upper'] = 'nvchecker'.upper()
+        self._docinfo['manual_section'] = '1'
+        self._docinfo['date'] = time.strftime('%Y-%m-%d')
+        self._docinfo['version'] = nvchecker.__version__
+      raise
+
+class MyWriter(manpage.Writer):
+  def __init__(self):
+    super().__init__()
+    self.translator_class = MyTranslator
+
+def main():
+  description = ("Generates plain unix manual documents.  " + default_description)
+  publish_cmdline(writer=MyWriter(), description=description)
+
+if __name__ == '__main__':
+  main()