Now `Zed` can display icons. The image below shows the icon of the
`zed.exe` file and the icon in the right-click properties.

I used the `crates\zed\resources\app-icon@2x.png` file to generate the
`.ico` file. Due to some blank space around the logo in the original
file, the logo appears slightly smaller on Windows compared to other
software.

The current `.ico` file contains logo files of multiple sizes: 16x16,
24x24, 32x32, 48x48, 64x64, 96x96, 128x128, 256x256, 512x512.
Release Notes:
- N/A
Currently when one runs `cargo build` twice without changing anything,
zed lib and binary are gonna get rebuilt every time. I checked out cargo
logs and it turns out we were querying wrong path to `.git/logs/HEAD` in
our build.rs, causing it to rerun on every build and thus marking zed
lib as dirty.
See logs (`CARGO_LOG=cargo::core::compiler::fingerprint=trace cargo
build`):
```
0.501173792s INFO cargo::core::compiler::fingerprint: fingerprint dirty for zed v0.120.0 (/Users/hiro/Projects/zed/crates/zed)/RunCustomBuild/TargetInner { ..: custom_build_target("build-script-build", "/Users/hiro/Projects/zed/crates/zed/build.rs", Edition2021) }
0.501180417s INFO cargo::core::compiler::fingerprint: dirty: FsStatusOutdated(StaleItem(MissingFile("/Users/hiro/Projects/zed/crates/zed/.git/logs/HEAD")))
```
The path to .git directory is relative to crates/zed and not to the
workspace's root.
/cc @maxbrunsfeld
Release Notes:
- N/A
I add /usr/lib/swift as an rpath, which seems to fix the issue even though
there doesn't seem to be a relevant library at that location on my machine.
Based on my research, wondering if `-Wl,-weak-lswiftCompatibilityConcurrency`
is also required for this to work on older OSes, but holding back for now.
* Generate the themes on build
* In debug builds, watch the theme sources. When they change, re-generate
the themes and reload the current theme, removing the need for the
`theme_selector::Reload` command.
Co-authored-by: Keith Simmons <keith@zed.dev>