Correct variable names in embed.fnc for hv_free_ent and hv_free_ent_ret.

Make the second variable name in embed.fnc match those used in the
actual function declaration.  This will matter if we add in 'entry'
to PERL_ARGS_ASSERT_HV_FREE_ENT_RET.  Also regen headers (only proto.h
is affected) to match.

embed.fnc

@@ -529,7 +529,7 @@ Ap	|void*	|hv_common_key_len|NULLOK HV *hv|NN const char *key \
 				|I32 klen_i32|const int action|NULLOK SV *val \
 				|const U32 hash
 Apod	|STRLEN	|hv_fill	|NN HV const *const hv
-Ap	|void	|hv_free_ent	|NN HV *hv|NULLOK HE *entryK
+Ap	|void	|hv_free_ent	|NN HV *hv|NULLOK HE *entry
 Apd	|I32	|hv_iterinit	|NN HV *hv
 ApdR	|char*	|hv_iterkey	|NN HE* entry|NN I32* retlen
 ApdR	|SV*	|hv_iterkeysv	|NN HE* entry
@@ -1770,7 +1770,7 @@ po	|SV*	|hfree_next_entry	|NN HV *hv|NN STRLEN *indexp
 #if defined(PERL_IN_HV_C)
 s	|void	|hsplit		|NN HV *hv
 s	|void	|hfreeentries	|NN HV *hv
-s	|SV*	|hv_free_ent_ret|NN HV *hv|NULLOK HE *entryK
+s	|SV*	|hv_free_ent_ret|NN HV *hv|NULLOK HE *entry
 sa	|HE*	|new_he
 sanR	|HEK*	|save_hek_flags	|NN const char *str|I32 len|U32 hash|int flags
 sn	|void	|hv_magic_check	|NN HV *hv|NN bool *needs_copy|NN bool *needs_store

proto.h

@@ -1549,7 +1549,7 @@ PERL_CALLCONV STRLEN	Perl_hv_fill(pTHX_ HV const *const hv)
 #define PERL_ARGS_ASSERT_HV_FILL	\
 	assert(hv)
 
-PERL_CALLCONV void	Perl_hv_free_ent(pTHX_ HV *hv, HE *entryK)
+PERL_CALLCONV void	Perl_hv_free_ent(pTHX_ HV *hv, HE *entry)
 			__attribute__nonnull__(pTHX_1);
 #define PERL_ARGS_ASSERT_HV_FREE_ENT	\
 	assert(hv)
@@ -5708,7 +5708,7 @@ STATIC struct xpvhv_aux*	S_hv_auxinit(HV *hv)
 	assert(hv)
 
 STATIC SV*	S_hv_delete_common(pTHX_ HV *hv, SV *keysv, const char *key, STRLEN klen, int k_flags, I32 d_flags, U32 hash);
-STATIC SV*	S_hv_free_ent_ret(pTHX_ HV *hv, HE *entryK)
+STATIC SV*	S_hv_free_ent_ret(pTHX_ HV *hv, HE *entry)
 			__attribute__nonnull__(pTHX_1);
 #define PERL_ARGS_ASSERT_HV_FREE_ENT_RET	\
 	assert(hv)