update docs for release 0.8.0 (#1419)

### What problem does this PR solve?

update docs for release 0.8.0

### Type of change

- [x] Documentation Update

---------

Co-authored-by: writinwaters <93570324+writinwaters@users.noreply.github.com>

graph/component/categorize.py

@@ -38,7 +38,7 @@ class CategorizeParam(GenerateParam):
         self.check_empty(self.category_description, "[Categorize] Category examples")
         for k, v in self.category_description.items():
             if not k: raise ValueError(f"[Categorize] Category name can not be empty!")
-            if not v["to"]: raise ValueError(f"[Categorize] 'To' of category {k} can not be empty!")
+            if not v.get("to"): raise ValueError(f"[Categorize] 'To' of category {k} can not be empty!")
 
     def get_prompt(self):
         cate_lines = []

graph/component/generate.py

@@ -72,7 +72,10 @@ class Generate(ComponentBase):
         for para in self._param.parameters:
             cpn = self._canvas.get_component(para["component_id"])["obj"]
             _, out = cpn.output(allow_partial=False)
-            kwargs[para["key"]] = "\n - ".join(out["content"])
+            if "content" not in out.columns:
+                kwargs[para["key"]] = "Nothing"
+            else:
+                kwargs[para["key"]] = "\n - ".join(out["content"])
 
         kwargs["input"] = input
         for n, v in kwargs.items():