src/goImpl: allow `-` as an acceptable char for interface names (package/variable)

Fixes golang/vscode-go#1670

Change-Id: I8cb308a98ac457cb5529f8256fd687fda794f585
GitHub-Last-Rev: 495b09be93817aeab80042ebf917fd401d7a839e
GitHub-Pull-Request: golang/vscode-go#1708
Reviewed-on: https://go-review.googlesource.com/c/vscode-go/+/343829
Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>
Trust: Hyang-Ah Hana Kim <hyangah@gmail.com>
Trust: Robert Findley <rfindley@google.com>
diff --git a/src/goImpl.ts b/src/goImpl.ts
index bf467ec..c9c59f4 100644
--- a/src/goImpl.ts
+++ b/src/goImpl.ts
@@ -15,7 +15,7 @@
 import vscode = require('vscode');
 
 // Supports only passing interface, see TODO in implCursor to finish
-const inputRegex = /^(\w+\ \*?\w+\ )?([\w./]+)$/;
+const inputRegex = /^(\w+\ \*?\w+\ )?([\w\.\-\/]+)$/;
 
 export function implCursor() {
 	const editor = vscode.window.activeTextEditor;