Backport fix invalid printf format to 2.9 branch (issue #3200).

Author: BsAtHome

src/emc/rs274ngc/rs274ngc_return.hh

@@ -77,8 +77,8 @@
 #define NCE_EQUAL_SIGN_MISSING_IN_PARAMETER_SETTING _("Equal sign missing in parameter setting")
 #define NCE_F_WORD_MISSING_WITH_INVERSE_TIME_ARC_MOVE _("F word missing with inverse time arc move")
 #define NCE_F_WORD_MISSING_WITH_INVERSE_TIME_G1_MOVE _("F word missing with inverse time g1 move")
-#define NCE_FILE_ENDED_WITH_NO_PERCENT_SIGN _("File ended with no percent sign (%)")
-#define NCE_FILE_ENDED_WITH_NO_PERCENT_SIGN_OR_PROGRAM_END _("File ended with no percent sign (%) or program end (M2)")
+#define NCE_FILE_ENDED_WITH_NO_PERCENT_SIGN _("File ended with no percent sign (%%)")
+#define NCE_FILE_ENDED_WITH_NO_PERCENT_SIGN_OR_PROGRAM_END _("File ended with no percent sign (%%) or program end (M2)")
 #define NCE_FILE_NAME_TOO_LONG _("File name too long")
 #define NCE_G_CODE_OUT_OF_RANGE _("G-code out of range")
 #define NCE_I_WORD_GIVEN_FOR_ARC_IN_YZ_PLANE _("I word given for arc in yz plane")