Revert "[Fix] Fix history key, as we use `{=` and not `{{` in templates"

conf/modules.d/history_redis.conf

 
 history_redis {
   #servers = 127.0.0.1:6379; # Redis server to store history
-  key_prefix = "rs_history{=HOSTNAME=}{=COMPRESS=}"; # Default key name template
+  key_prefix = "rs_history{{HOSTNAME}}{{COMPRESS}}"; # Default key name template
   nrows = 200; # Default rows limit
   compress = true; # Use zstd compression when storing data in redis
   subject_privacy = false; # subject privacy is off

lualib/lua_util.lua

 -- @param {boolean} skip_global_env don't export Rspamd superglobals
 -- @return {string} string containing replaced values
 -- @example
+-- lua_util.jinja_template("HELLO {{FOO}} {{BAR}}!", {['FOO'] = 'LUA', ['BAR'] = 'WORLD'})
 -- "HELLO LUA WORLD!"
 --]]
 exports.jinja_template = function(text, env, skip_global_env)
 -- @param {boolean} skip_global_env don't export Rspamd superglobals
 -- @return {string} string containing replaced values
 -- @example
+-- lua_util.jinja_template("HELLO {{FOO}} {{BAR}}!", {['FOO'] = 'LUA', ['BAR'] = 'WORLD'})
 -- "HELLO LUA WORLD!"
 --]]
 exports.jinja_template_file = function(filename, env, skip_global_env)

src/plugins/lua/history_redis.lua

 local redis_params
 
 local settings = {
-  key_prefix = 'rs_history{=HOSTNAME=}{=COMPRESS=}', -- default key name template
+  key_prefix = 'rs_history{{HOSTNAME}}{{COMPRESS}}', -- default key name template
   expire = nil, -- default no expire
   nrows = 200, -- default rows limit
   compress = true, -- use zstd compression when storing data in redis