LibGfx/WebP: Rename two variables to be a bit clearer

No behavior change.

Userland/Libraries/LibGfx/ImageFormats/WebPLoaderLossless.cpp

@@ -81,17 +81,17 @@ private:
 
 ErrorOr<CanonicalCode> CanonicalCode::from_bytes(ReadonlyBytes bytes)
 {
-    auto non_zero_symbols = 0;
-    auto last_non_zero = -1;
+    auto non_zero_symbol_count = 0;
+    auto last_non_zero_symbol = -1;
     for (size_t i = 0; i < bytes.size(); i++) {
         if (bytes[i] != 0) {
-            non_zero_symbols++;
-            last_non_zero = i;
+            non_zero_symbol_count++;
+            last_non_zero_symbol = i;
         }
     }
 
-    if (non_zero_symbols == 1)
-        return CanonicalCode(last_non_zero);
+    if (non_zero_symbol_count == 1)
+        return CanonicalCode(last_non_zero_symbol);
 
     return CanonicalCode(TRY(Compress::CanonicalCode::from_bytes(bytes)));
 }