fix(gen_vimfn_types): don't include tag before signature's line (#24492)

When signature is a bit long or there are too many tags, the tags appear
before the signature's line. Don't include the line with tags in the
previous function' docs.

Also fix lint warnings.

scripts/gen_vimfn_types.lua

@@ -95,6 +95,7 @@ local function process_source(source)
 
   local lines = {} --- @type string[]
   local last_f --- @type string?
+  local last_l --- @type string?
 
   for i = s, #src_lines do
     local l = src_lines[i]
@@ -104,11 +105,14 @@ local function process_source(source)
     local f = l:match('^([a-z][a-zA-Z0-9_]*)%(')
     if f then
       if last_f then
+        if last_l and last_l:find('*' .. f .. '()*', 1, true) then
+          lines[#lines] = nil
+        end
         funcs[last_f].desc = lines
       end
       last_f = f
       local sig = l:match('[^)]+%)')
-      local params = {} --- @type string[]
+      local params = {} --- @type table[]
       if sig then
         for param in string.gmatch(sig, '{([a-z][a-zA-Z0-9_]*)}') do
           local t = ARG_NAME_TYPES[param] or 'any'
@@ -125,6 +129,7 @@ local function process_source(source)
     else
       lines[#lines+1] = l:gsub('^(<?)\t\t', '%1'):gsub('\t', '  ')
     end
+    last_l = l
   end
 
   if last_f then