Define better prototype for "network" functions

src_common/network.h

@@ -13,8 +13,8 @@ typedef struct network_info_s {
 // Returns the current chain id. Defaults to 0 if txType was not found.
 uint64_t get_chain_id(void);
 // Returns a pointer to the network struct, or NULL if there is none.
-network_info_t *get_network(void);
+const network_info_t *get_network(void);
 // Returns a pointer to the network name, or NULL if there is none.
-char *get_network_name(void);
+const char *get_network_name(void);
 // Returns a pointer to the network ticker, or chainConfig->coinName if there is none.
-char *get_network_ticker(void);
+const char *get_network_ticker(void);