chore(pack): Document rust-analyzer.check.command behavior

lua/astrocommunity/pack/rust/README.md

@@ -8,7 +8,7 @@ This plugin pack does the following:
 - Adds [TOML language support](../toml)
 
 > [!NOTE]
-> This pack DOES not add `rust_analyzer`. This should be managed by rustup. To add it to rustup, run:  `rustup component add rust-analyzer`
+> This pack DOES not add `rust_analyzer`. This should be managed by rustup. To add it to rustup, run: `rustup component add rust-analyzer`
 
 ## Additional LSP Configuration Tweaks
 
@@ -42,3 +42,31 @@ return {
   },
 }
 ```
+
+## Use `cargo check` for `rust-analyzer.check.command`
+
+By default, this pack configures `rust-analyzer.check.command` to use `cargo clippy` instead of `cargo check`.
+
+In some cases (for example, on large projects where `cargo clippy` is slow), you may want to use `cargo check` instead.
+
+There is currently no way to configure `rust-analyzer` per project, [adding `rust-analyzer.toml` support is still in progress](https://github.com/rust-lang/rust-analyzer/issues/13529).
+If you want to use `cargo check` you can change the `rust-analyzer.check.command` globally like the following:
+
+```lua
+{
+  "AstroNvim/astrolsp",
+  opts = {
+    config = {
+      rust_analyzer = {
+        settings = {
+          ["rust-analyzer"] = {
+            check = {
+              command = "check",
+            },
+          },
+        }
+      },
+    },
+  },
+}
+```