This PR renames `String.endPos` to `String.rawEndPos`, as in a future
release the name `String.endPos` will be taken by the function that is
currently called `String.endValidPos`.
This PR introduces a simple script that adjusts module headers in a
package for use of the module system, without further minimizing import
or annotation use.
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Co-authored-by: Kim Morrison <477956+kim-em@users.noreply.github.com>