Hint at loop variables' concrete values: name them v (for value) or k (for key)

SC2302.md

@@ -6,9 +6,9 @@ Plus companion warning [[SC2303]]: `i is an array value, not a key. Use directly
 
 ```sh
 array=(foo bar)
-for i in "${array[@]}"
+for v in "${array[@]}"
 do
-  echo "Value is ${array[$i]}"
+  echo "Value is ${array[$v]}"
 done
 ```
 
@@ -17,19 +17,19 @@ done
 Either loop over values 
 
 ```sh
-for i in "${array[@]}"
+for v in "${array[@]}"
 do
-  echo "Value is $i"
+  echo "Value is $v"
 done
 ```
 
 or loop over keys:
 
 ```sh
-for i in "${!array[@]}"
+for k in "${!array[@]}"  # Note `!`
 do
-  echo "Key is $i"
-  echo "Value is ${array[$i]}"
+  echo "Key is $k"
+  echo "Value is ${array[$k]}"
 done
 ```
 
@@ -37,11 +37,11 @@ done
 
 ShellCheck found a `for` loop over array *values*, where the variable is used as an array *key*. 
 
-In the problematic example, the loop will print `Value is foo` twice. On the second iteration, `i=bar`, and `bar` is unset and considered zero, so `${array[$i]}` becomes `${array[bar]}` becomes `${array[0]}` becomes `foo`.
+In the problematic example, the loop will print `Value is foo` twice. On the second iteration, `v=bar`, and `bar` is unset and considered zero, so `${array[$v]}` becomes `${array[bar]}` becomes `${array[0]}` becomes `foo`.
 
-If you don't care about the key, simply loop over array values and use `$i` to refer to the array value, like in the first correct example.
+If you don't care about the key, simply loop over array values and use `$v` to refer to the array value, like in the first correct example.
 
-If you do want the key, loop over array keys with `"${!array[@]}"`, use `$i` to refer to the array key, and `${array[$i]}` to refer to the array value.
+If you do want the key, loop over array keys with `"${!array[@]}"`, use `$k` to refer to the array key, and `${array[$k]}` to refer to the array value.
 
 ### Exceptions: