DOC: fix listing na_values in read_csv docstring - add subsequent_indent to wrapped text (#15173)

Author: Thoralf Gutierrez

pandas/io/parsers.py

@@ -148,7 +148,8 @@
 na_values : scalar, str, list-like, or dict, default None
     Additional strings to recognize as NA/NaN. If dict passed, specific
     per-column NA values.  By default the following values are interpreted as
-    NaN: '""" + fill("', '".join(sorted(_NA_VALUES)), 70) + """'`.
+    NaN: '""" + fill("', '".join(sorted(_NA_VALUES)),
+                     70, subsequent_indent="    ") + """'`.
 keep_default_na : bool, default True
     If na_values are specified and keep_default_na is False the default NaN
     values are overridden, otherwise they're appended to.