test(Tcl): add shebang source files for regression test

CI reported FileNotFoundError for Tcl/{tclsh,expect,wish}_shebang in
tests/syntax-tests/source/Tcl/. The highlighted files existed but the
source files had been omitted, so create_highlighted_versions.py had
nothing to read from.

Source files match the shebang regression test inputs at
tests/examples/regression_tests/issue_3647_*.