snippets: add a placeholder for the for loop index

Fixes golang/vscode-go#734

Change-Id: I73bb97a34fc854dd837e4619026160093aeba524
GitHub-Last-Rev: 9a65cbbb3c79b2419dbe55b9b0fe2e4b3db0dd0a
GitHub-Pull-Request: golang/vscode-go#735
Reviewed-on: https://go-review.googlesource.com/c/vscode-go/+/259117
Reviewed-by: Suzy Mueller <suzmue@golang.org>
Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>
Trust: Suzy Mueller <suzmue@golang.org>
Trust: Hyang-Ah Hana Kim <hyangah@gmail.com>
diff --git a/snippets/go.json b/snippets/go.json
index 301ead3..b9c5434 100644
--- a/snippets/go.json
+++ b/snippets/go.json
@@ -62,7 +62,7 @@
 		},
 		"for statement": {
 			"prefix": "for",
-			"body": "for ${1:i} := 0; $1 < ${2:count}; $1${3:++} {\n\t$0\n}",
+			"body": "for ${1:i} := ${2:0}; $1 < ${3:count}; $1${4:++} {\n\t$0\n}",
 			"description": "Snippet for a for loop"
 		},
 		"for range statement": {