Avoid using the "else" conditional compilation macro directive

Even if "-else." is a valid directive:
  https://www.erlang.org/docs/28/system/macros.html#conditional-compilation
there is a bug in rebar3_format that annoyingly rewrites it as "- else ."
  https://github.com/AdRoll/rebar3_format/issues/337
as a quick workaround, rewrite directives to not use "-else."

src/ejabberd_web_admin.erl

@@ -1925,7 +1925,9 @@ lists_zipwith3(Combine, [E1 | List1], [E2 | List2], [], DefX, DefY, DefZ, Res) -
     E123 = Combine(E1, E2, DefZ),
     lists_zipwith3(Combine, List1, List2, [], DefX, DefY, DefZ, [E123 | Res]).
 
--else.
+-endif.
+
+-ifndef(OTP_BELOW_26).
 
 lists_zipwith3(Combine, List1, List2, List3, How) ->
     lists:zipwith3(Combine, List1, List2, List3, How).

src/mod_adhoc_api.erl

@@ -664,7 +664,9 @@ lists_zip3_pad([A | As], Nil, Nil, Xs) when (Nil == none) or (Nil == []) ->
 lists_zip3_pad([], Nil, Nil, Xs) when (Nil == none) or (Nil == []) ->
     lists:reverse(Xs).
 
--else.
+-endif.
+
+-ifndef(OTP_BELOW_26).
 
 lists_zip3_pad(As, Bs, Cs) ->
     lists:zip3(As, Bs, Cs, {pad, {error_missing_args_def, "", ""}}).

test/json_test.erl

@@ -11,7 +11,6 @@ encode_binary_test() ->
     Encoded = <<"\"This is an error text.\"">>,
     ?assertMatch(Encoded, misc:json_encode(Binary)).
 
--ifdef(OTP_BELOW_27).
 -ifdef(OTP_BELOW_26).
 
 %% OTP 25 or lower
@@ -24,7 +23,11 @@ encode_map_test() ->
         <<"{\"service\":\"conference\",\"name\":\"room\",\"jid\":\"user@server\",\"affiliation\":\"member\"}">>,
     ?assertMatch(Encoded, misc:json_encode(Map)).
 
--else.
+-endif.
+
+-ifdef(OTP_BELOW_27).
+
+-ifndef(OTP_BELOW_26).
 
 %% OTP 26
 encode_map_test() ->
@@ -37,8 +40,9 @@ encode_map_test() ->
     ?assertMatch(Encoded, misc:json_encode(Map)).
 
 -endif.
+-endif.
 
--else.
+-ifndef(OTP_BELOW_27).
 
 %% OTP 27 or higher or higher
 encode_map_test() ->