gen_vimdoc.py: skip "Parameters" header if all excluded

runtime/doc/api.txt

@@ -491,8 +491,6 @@ nvim_set_current_dir({dir})                           *nvim_set_current_dir()*
 nvim_get_current_line()                              *nvim_get_current_line()*
                 Gets the current line.
 
-                Parameters: ~
-
                 Return: ~
                     Current line string
 
@@ -505,8 +503,6 @@ nvim_set_current_line({line})                        *nvim_set_current_line()*
 nvim_del_current_line()                              *nvim_del_current_line()*
                 Deletes the current line.
 
-                Parameters: ~
-
 nvim_get_var({name})                                          *nvim_get_var()*
                 Gets a global (g:) variable.
 
@@ -1758,8 +1754,6 @@ nvim_ui_detach()                                            *nvim_ui_detach()*
 
                 Removes the client from the list of UIs. |nvim_list_uis()|
 
-                Parameters: ~
-
 nvim_ui_try_resize({width}, {height})                   *nvim_ui_try_resize()*
                 TODO: Documentation
 

scripts/gen_vimdoc.py

@@ -219,6 +219,14 @@ def doc_wrap(text, prefix='', width=70, func=False, indent=None):
     return result
 
 
+def has_nonexcluded_params(nodes):
+    """Returns true if any of the given <parameterlist> elements has at least
+    one non-excluded item."""
+    for n in nodes:
+        if render_params(n) != '':
+            return True
+
+
 def render_params(parent, width=62):
     """Renders Doxygen <parameterlist> tag as Vim help text."""
     name_length = 0
@@ -356,7 +364,7 @@ def render_para(parent, indent='', width=62):
 
     chunks = [text]
     # Generate text from the gathered items.
-    if len(groups['params']) > 0:
+    if len(groups['params']) > 0 and has_nonexcluded_params(groups['params']):
         chunks.append('\nParameters: ~')
         for child in groups['params']:
             chunks.append(render_params(child, width=width))