Update unicode-db.hpp to fix gcc 10 warnings

Author: cor3ntin

include/unicode-db/unicode-db.hpp

@@ -239,31 +239,39 @@ struct bool_trie {
     constexpr bool lookup(char32_t u) const {
         std::uint32_t c = u;
         if(c < 0x800) {
-            if constexpr(r1_s == 0)
+            if constexpr(r1_s == 0){
                 return false;
-            return trie_range_leaf(c, r1[c >> 6]);
+            }
+            else {
+                return trie_range_leaf(c, r1[c >> 6]);
+            }
         } else if(c < 0x10000) {
-            if constexpr(r3_s == 0)
+            if constexpr(r3_s == 0) {
                 return false;
-            std::size_t i = ((c >> 6) - 0x20);
-            auto child = 0;
-            if(i >= r2_t_f && i < r2_t_f + r2_s)
-                child = r2[i - r2_t_f];
-
-            return trie_range_leaf(c, r3[child]);
+            }
+            else {
+                std::size_t i = ((c >> 6) - 0x20);
+                auto child = 0;
+                if(i >= r2_t_f && i < r2_t_f + r2_s)
+                    child = r2[i - r2_t_f];
+                return trie_range_leaf(c, r3[child]);
+            }
         } else {
             if constexpr(r6_s == 0)
                 return false;
             std::size_t i4 = (c >> 12) - 0x10;
             auto child = 0;
-            if(i4 >= r4_t_f && i4 < r4_t_f + r4_s)
-                child = r4[i4 - r4_t_f];
-
+            if constexpr(r4_s > 0) {
+                if(i4 >= r4_t_f && i4 < r4_t_f + r4_s)
+                    child = r4[i4 - r4_t_f];
+            }
 
             std::size_t i5 = (child << 6) + ((c >> 6) & 0x3f);
             auto leaf = 0;
-            if(i5 >= r5_t_f && i5 < r5_t_f + r5_s)
-                leaf = r5[i5 - r5_t_f];
+            if constexpr(r5_s > 0) {
+                if(i5 >= r5_t_f && i5 < r5_t_f + r5_s)
+                    leaf = r5[i5 - r5_t_f];
+            }
             return trie_range_leaf(c, r6[leaf]);
         }
     }