[GN Docs] Fix typo

tools/gn/target_generator.cc

Index: tools/gn/target_generator.cc
diff --git a/tools/gn/target_generator.cc b/tools/gn/target_generator.cc
index 90642d47d201b36895f3c0693807e9befa5acec1..7fe64fd8b091ba5b1e3688b8c2aeffc52f45e060 100644
--- a/tools/gn/target_generator.cc
+++ b/tools/gn/target_generator.cc
@@ -305,7 +305,7 @@ bool TargetGenerator::FillOutputs(bool allow_substitutions) {
     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;
     }