sdbus++: generate markdown for errors

Change-Id: Iafdf4c30e312b0ef7faeea3e3a7379f1868a61dc
Signed-off-by: Patrick Williams <patrick@stwcx.xyz>
diff --git a/tools/sdbusplus/error.py b/tools/sdbusplus/error.py
index 55f5e6a..5243cda 100644
--- a/tools/sdbusplus/error.py
+++ b/tools/sdbusplus/error.py
@@ -23,6 +23,9 @@
 
         super(Error, self).__init__(**kwargs)
 
+    def markdown(self, loader):
+        return self.render(loader, "error.mako.md", error=self)
+
     def exception_header(self, loader):
         return self.render(loader, "error.mako.hpp", error=self)
 
diff --git a/tools/sdbusplus/templates/error.mako.md b/tools/sdbusplus/templates/error.mako.md
new file mode 100644
index 0000000..d22950a
--- /dev/null
+++ b/tools/sdbusplus/templates/error.mako.md
@@ -0,0 +1,7 @@
+${"##"} Errors
+
+% for e in error.errors:
+${"###"} ${e.name}
+
+${e.description}
+% endfor
diff --git a/tools/sdbusplus/templates/method.mako.md b/tools/sdbusplus/templates/method.mako.md
index 4a2f9d6..5fdebd4 100644
--- a/tools/sdbusplus/templates/method.mako.md
+++ b/tools/sdbusplus/templates/method.mako.md
@@ -13,3 +13,10 @@
 | out | ${r.markdown(loader)} |
     % endfor
 % endif
+
+% if len(method.errors):
+${"####"} Errors
+    % for e in method.errors:
+ * ${e}
+    % endfor
+% endif