Restore lsp-rust-analyzer-cargo-all-targets

This partially reverts #3893.

The rust-analyzer.checkOnSave.allTargets configuration still exists, although it
is internally renamed by rust-analyzer to rust-analyzer.check.allTargets which
is the new version. Maybe the intent was to remove lsp-rust-all-targets which is
indeed unused by lsp-rust.

Author: ia0

clients/lsp-rust.el

@@ -495,6 +495,12 @@ The command should include `--message=format=json` or similar option."
   :group 'lsp-rust-analyzer
   :package-version '(lsp-mode . "6.2.2"))
 
+(defcustom lsp-rust-analyzer-cargo-all-targets t
+  "Cargo watch all targets or not."
+  :type 'boolean
+  :group 'lsp-rust-analyzer
+  :package-version '(lsp-mode . "6.2.2"))
+
 (defcustom lsp-rust-analyzer-checkonsave-features []
   "List of features to activate.
 Set this to `\"all\"` to pass `--all-features` to cargo."
@@ -747,6 +753,7 @@ or JSON objects in `rust-project.json` format."
     :checkOnSave (:enable ,(lsp-json-bool lsp-rust-analyzer-cargo-watch-enable)
                   :command ,lsp-rust-analyzer-cargo-watch-command
                   :extraArgs ,lsp-rust-analyzer-cargo-watch-args
+                  :allTargets ,(lsp-json-bool lsp-rust-analyzer-cargo-all-targets)
                   :features ,lsp-rust-analyzer-checkonsave-features
                   :overrideCommand ,lsp-rust-analyzer-cargo-override-command)
     :files (:exclude ,lsp-rust-analyzer-exclude-globs