fix typoe in comment that made it misleading

tools/bazel-build-env

@@ -4,8 +4,8 @@
 
 # Although it is the traditional way of capturing the git version, it isn't so helpful because the
 # value is held in bazel's context and isn't available until execution time; not analysis. As a
-# result it can be used to generate variable target names. This script doesn't run early enough to
-# generate/update a file in-time for the load phase either.
+# result it canNOT be used to generate variable target names. This script doesn't run early enough
+# to generate/update a file in-time for the load phase either.
 #
 # Instead, prefer loading "versioning.bzl", which is generated by tools/bazel just before executing
 # the real bazel.