Merge branch 'tl/notes-separator'

Merge branch 'tl/notes-separator'

'git notes append' was taught '--separator' to specify string to insert
between paragraphs.

* tl/notes-separator:
  notes: introduce "--no-separator" option
  notes.c: introduce "--[no-]stripspace" option
  notes.c: append separator instead of insert by pos
  notes.c: introduce '--separator=<paragraph-break>' option
  t3321: add test cases about the notes stripspace behavior
  notes.c: use designated initializers for clarity
  notes.c: cleanup 'strbuf_grow' call in 'append_edit'