Add definition for scalar and link to it (#10810)

Author: sdwheeler

reference/5.1/Microsoft.PowerShell.Core/About/about_Assignment_Operators.md

@@ -1,7 +1,7 @@
 ---
 description: Describes how to use operators to assign values to variables.
 Locale: en-US
-ms.date: 08/01/2023
+ms.date: 01/19/2024
 online version: https://learn.microsoft.com/powershell/module/microsoft.powershell.core/about/about_assignment_operators?view=powershell-5.1&WT.mc_id=ps-gethelp
 schema: 2.0.0
 title: about Assignment Operators
@@ -15,8 +15,8 @@ Describes how to use operators to assign values to variables.
 
 Assignment operators assign one or more values to a variable. The equals sign
 (`=`) is the PowerShell assignment operator. PowerShell also has the following
-_compound_ assignment operators: `+=`, `-=`, `*=`, `%=`, `++`, `--`. Compound
-assignment operators perform numeric operations on the values before the
+_compound_ assignment operators: `+=`, `-=`, `*=`, `%=`, `++`, `--`, `??=`.
+Compound assignment operators perform operations on the values before the
 assignment.
 
 ## Syntax
@@ -321,10 +321,9 @@ $a
 ```
 
 You can't use the `-=` operator to delete the values of a variable. To delete
-all the values that are assigned to a variable, use the
-[Clear-Item](xref:Microsoft.PowerShell.Management.Clear-Item) or
-[Clear-Variable](xref:Microsoft.PowerShell.Utility.Clear-Variable) cmdlets
-to assign a value of `$null` or `""` to the variable.
+all the values that are assigned to a variable, use the [Clear-Item][06] or
+[Clear-Variable][07] cmdlets to assign a value of `$null` or `""` to the
+variable.
 
 ```powershell
 $a = $null
@@ -355,11 +354,9 @@ $a
 3
 ```
 
-To delete a variable, use the
-[Remove-Variable](xref:Microsoft.PowerShell.Utility.Remove-Variable)
-cmdlet. This method is useful when the variable is explicitly cast to a
-particular data type, and you want an untyped variable. The following command
-deletes the `$a` variable:
+To delete a variable, use the [Remove-Variable][08] cmdlet. This method is
+useful when the variable is explicitly cast to a particular data type, and you
+want an untyped variable. The following command deletes the `$a` variable:
 
 ```powershell
 Remove-Variable -Name a
@@ -416,8 +413,8 @@ $a[0] *= 2
 ### The assignment by division operator
 
 The assignment by division operator `/=` divides a numeric value by the value
-that's specified on the right side of the operator. The operator can't be
-used with string variables.
+that's specified on the right side of the operator. The operator can't be used
+with string variables.
 
 The `/=` operator combines two operations. First, it divides, and then it
 assigns. Therefore, the following two statements are equivalent:
@@ -681,10 +678,10 @@ $a
 9
 ```
 
-You can cast a new scalar variable as any .NET type by placing the type name in
-brackets that precede either the variable name or the first assignment value.
-When you cast a variable, you are defining the type of data that can be stored
-in the variable.
+You can cast a new [scalar][01] variable as any .NET type by placing the type
+name in brackets that precede either the variable name or the first assignment
+value. When you cast a variable, you are defining the type of data that can be
+stored in the variable.
 
 For example, the following command casts the variable as a string type:
 
@@ -811,9 +808,9 @@ $d, $e, $f = $c
 This command assigns the value 3 to the `$d` variable, the value 4 to the `$e`
 variable, and the value 5 to the `$f` variable.
 
-If the assignment value contains fewer elements than variables, the
-remaining variables are assigned the value `$null`. For example, the
-following command contains three variables and two values:
+If the assignment value contains fewer elements than variables, the remaining
+variables are assigned the value `$null`. For example, the following command
+contains three variables and two values:
 
 ```powershell
 $a, $b, $c = 1, 2
@@ -832,21 +829,29 @@ $a = $b = $c = $d = "three"
 
 ## Variable-related cmdlets
 
-In addition to using an assignment operation to set a variable value, you
-can also use the
-[Set-Variable](xref:Microsoft.PowerShell.Utility.Set-Variable) cmdlet. For
-example, the following command uses `Set-Variable` to assign an array of 1,
-2, 3 to the `$a` variable.
+In addition to using an assignment operation to set a variable value, you can
+also use the [Set-Variable][09] cmdlet. For example, the following command uses
+`Set-Variable` to assign an array of 1, 2, 3 to the `$a` variable.
 
 ```powershell
 Set-Variable -Name a -Value 1, 2, 3
 ```
 
 ## See also
 
-- [about_Arrays](about_Arrays.md)
-- [about_Hash_Tables](about_Hash_Tables.md)
-- [about_Variables](about_Variables.md)
-- [Clear-Variable](xref:Microsoft.PowerShell.Utility.Clear-Variable)
-- [Remove-Variable](xref:Microsoft.PowerShell.Utility.Remove-Variable)
-- [Set-Variable](xref:Microsoft.PowerShell.Utility.Set-Variable)
+- [about_Arrays][02]
+- [about_Hash_Tables][03]
+- [about_Variables][05]
+- [Clear-Variable][07]
+- [Remove-Variable][08]
+- [Set-Variable][09]
+
+<!-- link references -->
+[01]: /powershell/scripting/learn/glossary#scalar-value
+[02]: about_Arrays.md
+[03]: about_Hash_Tables.md
+[05]: about_Variables.md
+[06]: xref:Microsoft.PowerShell.Management.Clear-Item
+[07]: xref:Microsoft.PowerShell.Utility.Clear-Variable
+[08]: xref:Microsoft.PowerShell.Utility.Remove-Variable
+[09]: xref:Microsoft.PowerShell.Utility.Set-Variable