Fix multi-paragraph doxygen comments in functions

Previously multi-paragraph functions that used doxygen comments would
get the paragraphs merged into one.  This behaviour has now been fixed
to preserve the mult-paragraph nature.

Author: speedyleion

CHANGELOG.rst

@@ -15,6 +15,14 @@ Added
   Compilation args can now be specified with the
   ``c_autodoc_compilation_args`` configuration value.
 
+Fixes
+-----
+
+* Fix parsing of multi-paragraph function documentation that used doxygen style
+  markup.  Previously multi-paragraph function documentation which used doxygen
+  style markup would get merged in to one paragraph.  Now the multi-paragraph
+  nature is preserved.
+
 `v0.4.0`_ (2020-12-27)
 ==========================
 

src/sphinx_c_autodoc/loader.py

@@ -413,6 +413,10 @@ def get_soup_doc(self) -> Optional[str]:
         body = self.get_paragraph(root.find("abstract", recursive=False))
         body += self.get_paragraph(root.find("discussion", recursive=False))
 
+        # Single newlines are tread as the same paragraph in restructured text,
+        # providing 2 results in separate paragraphs.
+        body = body.replace("\n", "\n\n")
+
         for param in root.find_all("parameter"):
             name = param.find("name").text
             param_doc = self.get_paragraph(param.discussion)

tests/directives/test_autocfunction.py

@@ -117,3 +117,32 @@ def test_doc(self, function, expected_doc, sphinx_state):
         # For whatever reason the as text comes back with double spacing, so we
         # knock it down to single spacing to make the expected string smaller.
         assert body.astext().replace("\n\n", "\n") == dedent(expected_doc)
+
+    def test_multiple_paragraph_doxgyen_comment(self, sphinx_state):
+        """
+        Tests that when processing a multi paragraph doxygen comment that the
+        multiple paragraphs are preserved.
+        """
+        directive = AutodocDirective(
+            "autocfunction",
+            ["functions.c::doxy_documented_parameters_no_returns"],
+            {"members": None},
+            None,
+            None,
+            None,
+            None,
+            sphinx_state,
+            None,
+        )
+        output = directive.run()
+
+        # First item is the index entry
+        assert 2 == len(output)
+        body = output[1]
+
+        # first item is the function signature
+        paragraphs = body.children[1]
+
+        # 3 paragraphs from the description, and then one more child for the
+        # parameter listing
+        assert 4 == len(paragraphs)