Issue #17202: Add .bat to .hgeol to force them to CRLF.

Using LF can a script to fail if it tries to use a label that is
split across 512 byte blocks.  Who knows why.
diff --git a/.hgeol b/.hgeol
index 2919f76..2437601 100644
--- a/.hgeol
+++ b/.hgeol
@@ -40,6 +40,9 @@
 
 Lib/test/coding20731.py = BIN
 
+# Windows batch files work best with CRLF, there can be subtle problems with LF
+**.bat = CRLF
+
 # All other files (which presumably are human-editable) are "native".
 # This must be the last rule!