Add Compare link to README.md

[edrex]

I added a link to compare changes in main vs upstream master, which shows no changes. You can select another head branch from the /compare menu, and feel free to make any changes.

So I'm a little confused. Is there code? Was there a PR that made this unnecessary? Please update the docs with the latest status, in the interest of transparency. Thanks!

[usagi-flow]

Hmm the idea is great, but as you point out, GitHub fails to show the changes.

I'm not sure, but my guess would be that because this repository isn't registered as a "fork" of Helix, GH can't compare the repos. (See #9 for the reason why I changed the repo from a "fork" to a standalone repo).

The changes can be inspected quite easily with Git though, although that requires a local clone:

git clone https://github.com/usagi-flow/evil-helix.git
git remote add upstream https://github.com/helix-editor/helix.git
git fetch upstream
git diff --name-status upstream/master main

This will output something like this:

A       .forgejo/workflows/build.yaml
M       .github/workflows/build.yml
A       .github/workflows/evil-build-pr.yml
A       .github/workflows/evil-build-tag.yml
A       .github/workflows/evil-check-pr.yml
M       .github/workflows/gh-pages.yml
M       .github/workflows/release.yml
M       README.md
M       helix-core/src/lib.rs
A       helix-core/src/modeline.rs
M       helix-core/src/movement.rs
M       helix-core/src/syntax.rs
M       helix-loader/build.rs
M       helix-term/src/commands.rs
A       helix-term/src/commands/evil.rs
M       helix-term/src/config.rs
M       helix-term/src/keymap.rs
M       helix-term/src/keymap/default.rs
M       helix-term/src/main.rs
M       helix-term/src/ui/editor.rs
M       helix-term/src/ui/picker.rs
M       helix-term/src/ui/picker/handlers.rs
M       helix-term/src/ui/prompt.rs
M       helix-term/src/ui/statusline.rs
M       helix-tui/src/symbols.rs
M       helix-view/src/document.rs
M       helix-view/src/editor.rs
M       helix-view/src/theme.rs
M       languages.toml
M       runtime/themes/kanagawa.toml
M       runtime/tutor
M       screenshot.png

Of course, this is just an example. You can also remove --name-status for a complete diff, for instance.