fixed some typos

Signed-off-by: Frank Gadban <frankgad@outlook.de>

rootfs/etc/nginx/lua/balancer.lua

@@ -274,7 +274,7 @@ end
 function _M.init_worker()
   -- when worker starts, sync backends without delay
   -- we call it in timer because for endpoints that require
-  -- DNS resolution it needs to use socket which is not avalable in
+  -- DNS resolution it needs to use socket which is not available in
   -- init_worker phase
   local ok, err = ngx.timer.at(0, sync_backends)
   if not ok then

rootfs/etc/nginx/lua/test/util/dns_test.lua

@@ -57,7 +57,7 @@ describe("dns.lookup", function()
       assert.spy(spy_ngx_log).was_called_with(ngx.ERR, "failed to query the DNS server for ", "example.com", ":\n", "server returned error code: 1: format error\nserver returned error code: 1: format error")
     end)
 
-    it("retuns host when there's answer but no A/AAAA record in it", function()
+    it("returns host when there's answer but no A/AAAA record in it", function()
       helpers.mock_resty_dns_query(nil, { { name = "example.com", cname = "sub.example.com", ttl = 60 } })
       assert.are.same({ "example.com" }, dns_lookup("example.com"))
       assert.spy(spy_ngx_log).was_called_with(ngx.ERR, "failed to query the DNS server for ", "example.com", ":\n", "no A record resolved\nno AAAA record resolved")

rootfs/etc/nginx/lua/util.lua

@@ -173,7 +173,7 @@ local function tablelength(T)
 end
 _M.tablelength = tablelength
 
--- replaces special character value a with value b for all occurences in a
+-- replaces special character value a with value b for all occurrences in a
 -- string
 local function replace_special_char(str, a, b)
   return string.gsub(str, "%" .. a, b)