patch 8.2.4930: interpolated string expression requires escaping

Problem:    Interpolated string expression requires escaping.
Solution:   Do not require escaping in the expression.
diff --git a/src/proto/evalvars.pro b/src/proto/evalvars.pro
index 97bec7d..ce79435 100644
--- a/src/proto/evalvars.pro
+++ b/src/proto/evalvars.pro
@@ -13,6 +13,8 @@
 int get_spellword(list_T *list, char_u **pp);
 void prepare_vimvar(int idx, typval_T *save_tv);
 void restore_vimvar(int idx, typval_T *save_tv);
+char_u *eval_one_expr_in_str(char_u *p, garray_T *gap);
+char_u *eval_all_expr_in_str(char_u *str);
 list_T *heredoc_get(exarg_T *eap, char_u *cmd, int script_get, int vim9compile);
 void ex_var(exarg_T *eap);
 void ex_let(exarg_T *eap);
@@ -105,6 +107,4 @@
 void copy_callback(callback_T *dest, callback_T *src);
 void expand_autload_callback(callback_T *cb);
 void free_callback(callback_T *callback);
-char_u *eval_all_expr_in_str(char_u *str);
-
 /* vim: set ft=c : */