KCL: End-exclusive ranges like [0..<10] (#7179)

Closes https://github.com/KittyCAD/modeling-app/issues/6843

To clarify:
`[1..10]` is 1, 2, ..., 8, 9, 10
`[1..<10]` is 1, 2, ... 8, 9

rust/kcl-lib/src/lsp/kcl/mod.rs

@@ -1189,6 +1189,7 @@ impl LanguageServer for Backend {
     }
 
     async fn completion(&self, params: CompletionParams) -> RpcResult<Option<CompletionResponse>> {
+        // ADAM: This is the entrypoint.
         let mut completions = vec![CompletionItem {
             label: PIPE_OPERATOR.to_string(),
             label_details: None,