fix(docs): the runtimepath is not the runtime path

runtime/doc/api.txt

@@ -1133,7 +1133,7 @@ nvim_list_chans()                                          *nvim_list_chans()*
         specified at |nvim_get_chan_info()|.
 
 nvim_list_runtime_paths()                          *nvim_list_runtime_paths()*
-    Gets the paths contained in 'runtimepath'.
+    Gets the paths contained in |runtime-search-path|.
 
     Return: ~
         List of paths

src/nvim/api/vim.c

@@ -487,7 +487,7 @@ Integer nvim_strwidth(String text, Error *err)
   return (Integer)mb_string2cells(text.data);
 }
 
-/// Gets the paths contained in 'runtimepath'.
+/// Gets the paths contained in |runtime-search-path|.
 ///
 /// @return List of paths
 ArrayOf(String) nvim_list_runtime_paths(Error *err)