Add language server command for Crystal (#6948)

book/src/generated/lang-support.md

@@ -18,7 +18,7 @@
 | common-lisp | ✓ |  |  | `cl-lsp` |
 | cpon | ✓ |  | ✓ |  |
 | cpp | ✓ | ✓ | ✓ | `clangd` |
-| crystal | ✓ | ✓ |  |  |
+| crystal | ✓ | ✓ |  | `crystalline` |
 | css | ✓ |  |  | `vscode-css-language-server` |
 | cue | ✓ |  |  | `cuelsp` |
 | d | ✓ | ✓ | ✓ | `serve-d` |

languages.toml

@@ -253,6 +253,7 @@ roots = ["shard.yml", "shard.lock"]
 comment-token = "#"
 indent = { tab-width = 2, unit = "  " }
 grammar = "ruby"
+language-server = { command = "crystalline", args = ["--stdio"] }
 
 [[language]]
 name = "c-sharp"