Merge pull request #175 from PowerShell/NewRuleDocumentation

Add rule documentation for ProvideDefaultParameter

Author: yutingc

RuleDocumentation/ProvideDefaultParameterValue.md

@@ -0,0 +1,30 @@
+#ProvideDefaultParameterValue
+**Severity Level: Warning**
+
+
+##Description
+Parameters must have a default value as uninitialized parameters will lead to potential bugs in the scripts.
+
+##How to Fix
+
+To fix a violation of this rule, please specify a default value for all parameters.
+
+##Example
+
+Wrong： 
+
+```
+function Test($Param1)
+{
+	$Param1
+}
+```
+
+Correct: 
+
+```
+function Test($Param1 = $null)
+{
+	$Param1
+}
+```