Minor comments && Update outdated .expected

Author: jeongsoolee09

c/misra/src/rules/RULE-21-13/CtypeFunctionArgNotUnsignedCharOrEof.ql

@@ -30,6 +30,7 @@ where
     /* The argument's value should be in the EOF + `unsigned char` range. */
     -1 <= lowerBound(ctypeCallArgument) and upperBound(ctypeCallArgument) <= 255
   ) and
+  /* Only report control flow that is feasible (to avoid <ctype.h> functions implemented as macro). */
   ctypeCall.getBasicBlock().isReachable()
 select ctypeCall,
   "The <ctype.h> function " + ctypeCall + " accepts an argument " +

c/misra/test/rules/RULE-21-13/CtypeFunctionArgNotUnsignedCharOrEof.expected

@@ -1,2 +1,2 @@
-| test.c:17:7:17:17 | call to islower | The <ctype.h> function call to islower accepts an argument c3 that is not an unsigned char nor an EOF. |
-| test.c:23:7:23:17 | call to isdigit | The <ctype.h> function call to isdigit accepts an argument c4 that is not an unsigned char nor an EOF. |
+| test.c:14:7:14:13 | call to isalnum | The <ctype.h> function call to isalnum accepts an argument c3 that is not an unsigned char nor an EOF. |
+| test.c:20:7:20:13 | call to isalnum | The <ctype.h> function call to isalnum accepts an argument c4 that is not an unsigned char nor an EOF. |

c/misra/test/rules/RULE-21-13/test.c

@@ -20,8 +20,8 @@ void sample() {
       isalnum(c4); // NON_COMPLIANT: is outside unsigned char range of [0, 255]
 
   int c5 = getchar();
-  int r5 = isalnum(c5); // COMPLIANT[FALSE_POSITIVE]: library functions like
-                        // getchar needs to be modelled
+  int r5 = isalnum(
+      c5); // COMPLIANT: <stdio.h> source functions like getchar are modelled
 
   unsigned char x7;
   int c6;