Fix "go to label" in bazel LSP (#100)

Summary:
When executing "go to definition" on a label, it would previously go to the correct file but not to the definition of that target. This was because we were searching for a function call where the name is the whole label. Now it parses the label, using the label parser introduced in #101, to extract the name and searches using that.

Pull Request resolved: #100

Reviewed By: wendy728

Differential Revision: D52954185

Pulled By: ndmitchell

fbshipit-source-id: 937da257b7441d8abe313015ca1c8241c7967a10

Author: cameron-martin

starlark_bin/bin/bazel.rs

@@ -745,10 +745,12 @@ impl LspContext for BazelContext {
                     location_finder: if same_filename {
                         None
                     } else {
-                        let literal = literal.to_owned();
-                        Some(Box::new(move |ast| {
-                            Ok(ast.find_function_call_with_name(&literal))
-                        }))
+                        match Label::parse(literal) {
+                            Err(_) => None,
+                            Ok(label) => Some(Box::new(move |ast| {
+                                Ok(ast.find_function_call_with_name(&label.name))
+                            })),
+                        }
                     },
                 })
             })