Update sample (was SC1071); add related resources

SC1103.md

@@ -3,7 +3,8 @@
 ### Problematic code:
 
 ```sh
-#!/bin/zsh
+# shellcheck shell=zsh
+export PAGER=less
 ```
 
 ### Correct code:
@@ -11,7 +12,8 @@
 Any supported shell on the shebang or the `-s` option
 
 ```sh
-#!/bin/sh
+# shellcheck shell=sh
+export PAGER=less
 ```
 
 ### Rationale:
@@ -28,3 +30,10 @@ The supported shell types are listed in the help context, at the moment these ar
 * bash
 * dash
 * ksh
+
+### Related resources:
+
+- Similar rules
+   - [[SC1008]] - unrecognized shebang
+   - [[SC1071]] - unsupported shebang
+- [[Documentation for shell directive|Directive#shell]]