docs(waterdata.xarray): emit valid numpydoc from the wrapper docstrings

_xr_doc prepended a 4-space-indented note to the wrapped getter's docstring;
because the wrapped first line is unindented, inspect.getdoc's dedent broke and
left the Parameters/Returns sections over-indented, so napoleon (the package
uses numpydoc) mis-rendered them. Build a column-0 summary paragraph and append
the cleandoc'd body so the combined docstring is valid numpydoc.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: thodson-usgs

dataretrieval/waterdata/xarray.py

@@ -40,6 +40,7 @@
 from __future__ import annotations
 
 import datetime as _dt
+import inspect as _inspect
 import re as _re
 import warnings as _warnings
 from collections.abc import Callable
@@ -761,13 +762,18 @@ def _xr_doc(func, *, cf_metadata=True, allow_dense=True):
             "(always ragged; discrete samples are too sparse for a dense grid, "
             "so ``dense=`` does not apply)"
         )
+    # A column-0 summary paragraph + a cleandoc'd body keeps the combined
+    # docstring valid numpydoc (the wrapped getter's first line is unindented
+    # but its body is source-indented, which would otherwise break dedent and
+    # over-indent the Parameters/Returns sections).
     note = (
-        "    xarray wrapper: same arguments as "
-        f"``dataretrieval.waterdata.{func.__name__}``, but returns\n"
-        f"    {returns}. Hash-valued ID columns are always omitted here;\n"
-        "    the ``include_hash`` flag does not apply.\n\n"
+        "xarray wrapper: same arguments as "
+        f"``dataretrieval.waterdata.{func.__name__}``, but returns {returns}. "
+        "Hash-valued ID columns are always omitted here; the ``include_hash`` "
+        "flag does not apply."
     )
-    return note + (func.__doc__ or "")
+    body = _inspect.cleandoc(func.__doc__) if func.__doc__ else ""
+    return f"{note}\n\n{body}" if body else note
 
 
 @dataclass(frozen=True)