cargo: enable the watchman feature by default

I think the feature is requested by enough users that we should
include it by default, also for people who install from source (we
include it in the `packaging` feature already).

It increases the size of the binary from 16.5 MiB to 17.8 MiB. I
suspect we'd see some of that increase in size soon anyway, as I'm
probably going to use Tokio for making async backend requests.

CHANGELOG.md

@@ -15,6 +15,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   to limit the depth of the ancestor set. For example, use `jj log -r 
   'ancestors(@, 5)` to view the last 5 commits.
 
+* Support for the Watchman filesystem monitor is now bundled by default. Set
+  `core.fsmonitor = "watchman"` in your repo to enable.
+
 ### Fixed bugs
 
 ## [0.9.0] - 2023-09-06

cli/Cargo.toml

@@ -74,8 +74,8 @@ test-case = { workspace = true }
 testutils = { workspace = true }
 
 [features]
-default = []
+default = ["watchman"]
 bench = ["dep:criterion"]
-packaging = ["watchman"]
+packaging = []
 vendored-openssl = ["git2/vendored-openssl", "jj-lib/vendored-openssl"]
 watchman = ["jj-lib/watchman"]

docs/config.md

@@ -526,14 +526,6 @@ snapshots without having to rescan the entire working copy.
 
 ### Watchman
 
-The [Watchman filesystem monitor](https://facebook.github.io/watchman/) is
-currently only enabled if you compile jj with the `watchman` feature, such as
-with the following invocation:
-
-```shell
-cargo install --git https://github.com/martinvonz/jj.git --locked --bin jj jj-cli --features watchman
-```
-
 To configure the Watchman filesystem monitor, set
 `core.fsmonitor = "watchman"`. Ensure that you have [installed the Watchman
 executable on your system](https://facebook.github.io/watchman/docs/install).