Optimize file handling in the find module (#38192)

* Optimize file handling

Use the best practice of opening and doing operations on an opened file

Signed-off-by: Daniel Andrei Minca <mandrei17@gmail.com>

* Fix docstring to Sphinx type

- update the docstrings to Sphinx type, as suggested by Toshio
- Move the pattern object assignment outside the context manager, as
  suggested by Matt

Signed-off-by: Daniel Andrei Minca <mandrei17@gmail.com>

lib/ansible/modules/files/find.py

@@ -250,19 +250,24 @@ def sizefilter(st, size):
 
 
 def contentfilter(fsname, pattern):
-    '''filter files which contain the given expression'''
+    """
+    Filter files which contain the given expression
+    :arg fsname: Filename to scan for lines matching a pattern
+    :arg pattern: Pattern to look for inside of line
+    :rtype: bool
+    :returns: True if one of the lines in fsname matches the pattern. Otherwise False
+    """
     if pattern is None:
         return True
 
-    try:
-        f = open(fsname)
     prog = re.compile(pattern)
+
+    try:
+        with open(fsname) as f:
             for line in f:
                 if prog.match(line):
-                f.close()
                     return True
 
-        f.close()
     except:
         pass