feat(generate): insert links/tags sections at the cursor line too

Extend the cursor-line insertion from :NuwikiTOC to the other buffer
list generators: :NuwikiGenerateLinks and :NuwikiGenerateTagLinks. They
appended at end-of-file; a fresh section now goes at the cursor line
(with a leading blank), matching :NuwikiTOC. An existing section is still
refreshed in place, and the auto_generate_*-on-save hooks are unaffected
(they only ever replace).

Shared section_insert() helper computes the insert position/block for all
three (cursor line clamped to the document, else the per-command fallback:
top of file for TOC, EOF for links/tags). Clients send the 0-based cursor
line; handlers parse it via parse_uri_line_arg and thread it through
links_edit / tag_links_edit. Rebuild variants pass None.

Tests: links_edit_inserts_at_cursor_line + tag_links_edit_inserts_at_cursor_line.
577 passed, clippy clean, keymap harnesses green. Docs updated.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

autoload/nuwiki/commands.vim

@@ -734,11 +734,14 @@ endfunction
 " `generateForPath`). Matches upstream's optional path argument.
 function! nuwiki#commands#links_generate(...) abort
   let l:path = a:0 >= 1 ? a:1 : ''
+  " Cursor line (0-based) so a fresh section is inserted there.
+  let l:line = line('.') - 1
   if l:path !=# ''
     call s:exec('nuwiki.links.generateForPath',
-          \ [{'uri': s:buf_uri(), 'path': l:path}])
+          \ [{'uri': s:buf_uri(), 'path': l:path, 'line': l:line}])
   else
-    call s:exec('nuwiki.links.generate', [{'uri': s:buf_uri()}])
+    call s:exec('nuwiki.links.generate',
+          \ [{'uri': s:buf_uri(), 'line': l:line}])
   endif
 endfunction
 function! nuwiki#commands#check_links(...) abort
@@ -800,7 +803,8 @@ function! nuwiki#commands#tags_search(query) abort
 endfunction
 
 function! nuwiki#commands#tags_generate_links(tag) abort
-  let l:args = { 'uri': s:buf_uri() }
+  " Cursor line (0-based) so a fresh section is inserted there.
+  let l:args = { 'uri': s:buf_uri(), 'line': line('.') - 1 }
   if a:tag !=# ''
     let l:args['tag'] = a:tag
   endif