Merge branch 'mh/fetch-tags-in-addition-to-normal-refs'

Merge branch 'mh/fetch-tags-in-addition-to-normal-refs'

The "--tags" option to "git fetch" used to be literally a synonym to
a "refs/tags/*:refs/tags/*" refspec, which meant that (1) as an
explicit refspec given from the command line, it silenced the lazy
"git fetch" default that is configured, and (2) also as an explicit
refspec given from the command line, it interacted with "--prune"
to remove any tag that the remote we are fetching from does not
have.

This demotes it to an option; with it, we fetch all tags in
addition to what would be fetched without the option, and it does
not interact with the decision "--prune" makes to see what
remote-tracking refs the local has are missing the remote
counterpart.

* mh/fetch-tags-in-addition-to-normal-refs: (23 commits)
  fetch: improve the error messages emitted for conflicting refspecs
  handle_duplicate(): mark error message for translation
  ref_remote_duplicates(): extract a function handle_duplicate()
  ref_remove_duplicates(): simplify loop logic
  t5536: new test of refspec conflicts when fetching
  ref_remove_duplicates(): avoid redundant bisection
  git-fetch.txt: improve description of tag auto-following
  fetch-options.txt: simplify ifdef/ifndef/endif usage
  fetch, remote: properly convey --no-prune options to subprocesses
  builtin/remote.c:update(): use struct argv_array
  builtin/remote.c: reorder function definitions
  query_refspecs(): move some constants out of the loop
  fetch --prune: prune only based on explicit refspecs
  fetch --tags: fetch tags *in addition to* other stuff
  fetch: only opportunistically update references based on command line
  get_expanded_map(): avoid memory leak
  get_expanded_map(): add docstring
  builtin/fetch.c: reorder function definitions
  get_ref_map(): rename local variables
  api-remote.txt: correct section "struct refspec"
  ...