Wrong message numbers for “not yet installed” / “some failure” (1.14/1.15 instead of 1.15/1.16) #25

Found while checking the Polish translation against src/share.c (FDOS/share master 9ebf227):

• share.c:1102 catgets(cat, 1, 14, msg_notinstalled) - 1.14 is "removed."; it should be 1.15 ("cannot remove, not yet installed.").
• share.c:1105 catgets(cat, 1, 15, msg_somefailure) - it should be 1.16 ("cannot remove, some failure.").

With any NLS file present, SHARE /U without SHARE loaded prints "removed." instead of "not yet installed" (same class of bug as FDOS/move#7). English without NLS is fine, because the built-in defaults are correct.

Also: key 1.21 ("failed to free environment block", share.c:948) is in nls/share.en here, but not in fd-nls share/nls/share.en - I'll add it there so it can be translated.

Note: FreeDOS T2610 still ships SHARE 08/2006a without NLS, so this matters once a build from this repository is packaged. Happy to send a PR with the two-number fix.