handled empty section name whitespaces

Author: jspaezp

pydocstringformatter/_formatting/formatters_numpydoc.py

@@ -121,7 +121,10 @@ def treat_sections(
                 # summary.  They have neither a section header nor the
                 # line of hyphens after it.
                 indent_length = section_lines[1].index("-")
-                section_lines[1] = " " * indent_length + "-" * len(section_name)
+
+                if section_name:
+                    section_lines[1] = " " * indent_length + "-" * len(section_name)
+
                 if first_section:
                     # If the second line were not hyphens, the section name
                     # would be summary.  This assumes triple quotes, but that

tests/data/format/multi_style/numpydoc_parameter_spacing.py.out

@@ -43,7 +43,7 @@ def sincos(theta):
         If `theta` is not a float.
 
 
-
+    ----
     sin: float
         the sine of theta
     cos: float