Stop excluding base::return() and base::function from completions (#768)

* Stop excluding `base::return()` from completions

* Stop excluding `base::function` from completions

Author: jennybc

crates/ark/src/lsp/completions/sources/composite/search_path.rs

@@ -53,7 +53,7 @@ fn completions_from_search_path(
     let mut completions = vec![];
 
     const R_CONTROL_FLOW_KEYWORDS: &[&str] = &[
-        "if", "else", "for", "in", "while", "repeat", "break", "next", "return", "function",
+        "if", "else", "for", "in", "while", "repeat", "break", "next",
     ];
 
     unsafe {