Restore comment at appendShellString().
Commit b380a56a3f9556588a89013b765d67947d54f7d0 removed a paragraph, but
two of the paragraph's three sentences remained relevant.
Backpatch-through: 19
Branch
------
master
Details
-------
https://git.postgresql.org/pg/commitdiff/cfa573cf8cbdcbf7cbcae34911bd1ee292abdd2f
Modified Files
--------------
src/fe_utils/string_utils.c | 4 ++++
1 file changed, 4 insertions(+)
