run-command API: rename "env_array" to "env"

Start following-up on the rename mentioned in c7c4bdeccf3 (run-command
API: remove "env" member, always use "env_array", 2021-11-25) of
"env_array" to "env".

The "env_array" name was picked in 19a583dc39e (run-command: add
env_array, an optional argv_array for env, 2014-10-19) because "env"
was taken. Let's not forever keep the oddity of "*_array" for this
"struct strvec", but not for its "args" sibling.

This commit is almost entirely made with a coccinelle rule[1]. The
only manual change here is in run-command.h to rename the struct
member itself and to change "env_array" to "env" in the
CHILD_PROCESS_INIT initializer.

The rest of this is all a result of applying [1]:

 * make contrib/coccinelle/run_command.cocci.patch
 * patch -p1 <contrib/coccinelle/run_command.cocci.patch
 * git add -u

1. cat contrib/coccinelle/run_command.pending.cocci
   @@
   struct child_process E;
   @@
   - E.env_array
   + E.env

   @@
   struct child_process *E;
   @@
   - E->env_array
   + E->env

I've avoided changing any comments and derived variable names here,
that will all be done in the next commit.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/hook.c b/hook.c
index 1d51be3..2b47bdf 100644
--- a/hook.c
+++ b/hook.c
@@ -54,7 +54,7 @@ static int pick_next_hook(struct child_process *cp,
 		return 0;
 
 	cp->no_stdin = 1;
-	strvec_pushv(&cp->env_array, hook_cb->options->env.v);
+	strvec_pushv(&cp->env, hook_cb->options->env.v);
 	cp->stdout_to_stderr = 1;
 	cp->trace2_hook_name = hook_cb->hook_name;
 	cp->dir = hook_cb->options->dir;