Update Rust crate lsp-server to v0.7.8 (#15109)

This PR contains the following updates:

| Package | Type | Update | Change |
|---|---|---|---|
| [lsp-server](https://redirect.github.com/rust-lang/rust-analyzer)
([source](https://redirect.github.com/rust-lang/rust-analyzer/tree/HEAD/lib/lsp-server))
| workspace.dependencies | patch | `0.7.7` -> `0.7.8` |

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Cargo.lock

@@ -1607,13 +1607,14 @@ checksum = "a7a70ba024b9dc04c27ea2f0c0548feb474ec5c54bba33a7f72f873a39d07b24"
 
 [[package]]
 name = "lsp-server"
-version = "0.7.7"
+version = "0.7.8"
 source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "550446e84739dcaf6d48a4a093973850669e13e8a34d8f8d64851041be267cd9"
+checksum = "9462c4dc73e17f971ec1f171d44bfffb72e65a130117233388a0ebc7ec5656f9"
 dependencies = [
  "crossbeam-channel",
  "log",
  "serde",
+ "serde_derive",
  "serde_json",
 ]