tools: fix some typos

Change-Id: Iaad847631b9d5ee40558fcf9d51f4dfa99600e6b
GitHub-Last-Rev: 6fcb64f8d9a093e7bd949e5d28bd1176c27005c0
GitHub-Pull-Request: golang/tools#372
Reviewed-on: https://go-review.googlesource.com/c/tools/+/389595
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Hyang-Ah Hana Kim <hyangah@gmail.com>
gopls-CI: kokoro <noreply+kokoro@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Trust: Hyang-Ah Hana Kim <hyangah@gmail.com>
diff --git a/internal/lsp/source/api_json.go b/internal/lsp/source/api_json.go
index 1db1700..f2aff10 100755
--- a/internal/lsp/source/api_json.go
+++ b/internal/lsp/source/api_json.go
@@ -158,7 +158,7 @@
 			{
 				Name:      "experimentalPostfixCompletions",
 				Type:      "bool",
-				Doc:       "experimentalPostfixCompletions enables artifical method snippets\nsuch as \"someSlice.sort!\".\n",
+				Doc:       "experimentalPostfixCompletions enables artificial method snippets\nsuch as \"someSlice.sort!\".\n",
 				Default:   "true",
 				Status:    "experimental",
 				Hierarchy: "ui.completion",