Minor fix to documentation for let instruction.

Author: Bob Garner

docs/etl/ETL_Instructions.md

@@ -64,15 +64,14 @@ Assigns the resulting value after evaluating the provided *expression* to the pr
 
 #### Usage
 
-> `$[let `*variable*` = `*expression*`]`
+> `$[let `*variable*` `*assignmentOperator*` `*expression*`]`
 
 #### Arguments
 
 | Argument | Type | Description |
 |----------|------|-------------|
 | *variable* | `String` | The variable to receive the assigned value. |
-| *assignmentOperator* | `Operator` | The operator (if any) used with the = sign (e.g. += would supply the + operator here). |
-| *assignmentOperatorSymbolType* | `int` | This is the template parser's grammar ID essentially of the +=, -=, etc. operator. |
+| *assignmentOperator* | `Operator` | Typically this is just `=` but also supported are `+=`, `-=`, `*=` and `/=`. The `+=` can be used with string variables to concatenate string values. |
 | *expression* | `FTExpression` | The expression that will be evaluated. |
 
 <a name="category_context"></a>

src/main/java/org/entityc/compiler/transform/template/tree/FTLet.java

@@ -22,7 +22,7 @@
 
 @TemplateInstruction(category = TemplateInstructionCategory.ASSIGNMENT,
         name = "let",
-        usage = "`let `*variable*` = `*expression*",
+        usage = "`let `*variable*` `*assignmentOperator*` `*expression*",
         summary = "This is a straight forward way to assign values to a variable.",
         description = "Assigns the resulting value after evaluating the provided *expression* to the provided *variable*.")
 public class FTLet extends FTNode {
@@ -38,13 +38,10 @@ public FTLet(ParserRuleContext ctx,
                  )
                  String variable,
                  @TemplateInstructionArgument(
-                         description = "The operator (if any) used with the = sign (e.g. += would supply "
-                                       + "the + operator here)."
+                         description = "Typically this is just `=` but also supported are `+=`, `-=`, `*=` and `/=`. "
+                                       + "The `+=` can be used with string variables to concatenate string values."
                  )
                  FTOperation.Operator assignmentOperator,
-                 @TemplateInstructionArgument(
-                         description = "This is the template parser's grammar ID essentially of the +=, -=, etc. operator."
-                 )
                  int assignmentOperatorSymbolType,
                  @TemplateInstructionArgument(
                          description = "The expression that will be evaluated."