Add warning in function documentation

The function parsing "ip route" output modifies the input buffer to
tokenize in place. This must be mentioned in the function documentation.

app/src/adb_parser.h

@@ -7,6 +7,8 @@
 
 /**
  * Parse the ip from the output of `adb shell ip route`
+ *
+ * Warning: this function modifies the buffer for optimization purposes.
  */
 char *
 sc_adb_parse_device_ip_from_output(char *buf, size_t buf_len);