Remove experimental version + qhelp fixes

Author: joefarebrother

python/ql/src/Security/CWE-074/TemplateInjection.qhelp

@@ -16,10 +16,10 @@
         <sample src="examples/JinjaBad.py" />
 
         <p>The following is an example of a string that could be used to cause remote code execution when interpreted as a template:</p>
-        <sample src="examples/template_exploit" />
+        <sample src="examples/template_exploit.txt" />
 
         <p>In the following case, user input is not used to construct the template; rather is only used for as the parameters to render the template, which is safe.</p>
-        <sample scr="examples/JinjaGoodParam" />
+        <sample src="examples/JinjaGoodParam.py" />
 
         <p>In the following case, a <code>SandboxedEnvironment</code> is used, preventing remote code execution.</p>
         <sample src="examples/JinjaGoodSandbox.py" />