Fix ResourceWarning: add exception handling for file operations in tnc.py

Co-authored-by: bact <128572+bact@users.noreply.github.com>

Author: Copilot

pythainlp/corpus/tnc.py

@@ -58,11 +58,14 @@ def bigram_word_freqs() -> dict[tuple[str, str], int]:
         return freqs
     path = str(path)
 
-    with open(path, encoding="utf-8-sig") as fh:
-        for line in fh:
-            temp = line.strip().split("	")
-            if len(temp) >= 3:
-                freqs[(temp[0], temp[1])] = int(temp[-1])
+    try:
+        with open(path, encoding="utf-8-sig") as fh:
+            for line in fh:
+                temp = line.strip().split("	")
+                if len(temp) >= 3:
+                    freqs[(temp[0], temp[1])] = int(temp[-1])
+    except (IOError, OSError):
+        pass
 
     return freqs
 
@@ -76,10 +79,13 @@ def trigram_word_freqs() -> dict[tuple[str, str, str], int]:
         return freqs
     path = str(path)
 
-    with open(path, encoding="utf-8-sig") as fh:
-        for line in fh:
-            temp = line.strip().split("	")
-            if len(temp) >= 4:
-                freqs[(temp[0], temp[1], temp[2])] = int(temp[-1])
+    try:
+        with open(path, encoding="utf-8-sig") as fh:
+            for line in fh:
+                temp = line.strip().split("	")
+                if len(temp) >= 4:
+                    freqs[(temp[0], temp[1], temp[2])] = int(temp[-1])
+    except (IOError, OSError):
+        pass
 
     return freqs