[GN Docs] Fix typo

s/targe/target

BUG=None

Review-Url: https://codereview.chromium.org/2148593002
Cr-Original-Commit-Position: refs/heads/master@{#404882}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: 6af98e7151e6f8846e97a0390bcbe4df7b4150d6
diff --git a/tools/gn/target_generator.cc b/tools/gn/target_generator.cc
index 90642d4..7fe64fd 100644
--- a/tools/gn/target_generator.cc
+++ b/tools/gn/target_generator.cc
@@ -305,7 +305,7 @@
     if (!outputs.required_types().empty()) {
       *err_ = Err(*value, "Source expansions not allowed here.",
           "The outputs of this target used source {{expansions}} but this "
-          "targe type\ndoesn't support them. Just express the outputs "
+          "target type\ndoesn't support them. Just express the outputs "
           "literally.");
       return false;
     }