dmypy: add page (#17292)

Co-authored-by: Dylan <145150333+dmmqz@users.noreply.github.com>

pages/common/dmypy.md

@@ -0,0 +1,21 @@
+# dmypy
+
+> Type check Python code, running `mypy` as a daemon for better speed.
+> See also: `mypy` for more options to use with check and run.
+> More information: <https://mypy.readthedocs.io/en/stable/mypy_daemon.html>.
+
+- Type check a file, and start the daemon if it is not running:
+
+`dmypy check -- {{path/to/file.py}}`
+
+- Start the daemon:
+
+`dmypy start`
+
+- Type check a file (requires the daemon to be running):
+
+`dmypy run -- {{path/to/file.py}}`
+
+- Stop the daemon:
+
+`dmypy stop`