run.bat: comment text properly

LGTM=bradfitz
R=golang-codereviews, bradfitz
CC=golang-codereviews
https://golang.org/cl/153830044

src/run.bat

@@ -90,7 +90,7 @@ go run "%GOROOT%\test\run.go" - ..\misc\cgo\stdio
 if errorlevel 1 goto fail
 echo.
 
-# cgo tests inspect the traceback for runtime functions
+:: cgo tests inspect the traceback for runtime functions
 set OLDGOTRACEBACK=%GOTRACEBACK%
 set GOTRACEBACK=2