Escape underscores

Change-Id: Iab394fd02cb3589223efca95fa3773e0de2f7f36
diff --git a/src/tech/input/input-device-configuration-files.md b/src/tech/input/input-device-configuration-files.md
index 0a477d0..be6900a 100644
--- a/src/tech/input/input-device-configuration-files.md
+++ b/src/tech/input/input-device-configuration-files.md
@@ -62,7 +62,7 @@
 *   `/data/system/devices/idc/DEVICE_NAME.idc`
 
 When constructing a file path that contains the device name, all characters
-in the device name other than '0'-'9', 'a'-'z', 'A'-'Z', '-' or '_' are replaced by '_'.
+in the device name other than '0'-'9', 'a'-'z', 'A'-'Z', '-' or '\_' are replaced by '\_'.
 
 ## Syntax ##