Tweak - Move the stranded docblock onto the method it documents.

The docblock for test_get_backend_line_items_sends_shipping_only_status_as_exempt()
sat above the cart-path test instead, leaving the backend test with no docblock.
PHPCS binds a docblock to the immediately following token, so the orphan became a
floating comment and Squiz.Commenting.FunctionComment.Missing fired on the method
60 lines below it.

WordPress-Docs loads globally in .phpcs.php.xml and its tests/ exclusions do not
cover Squiz.Commenting.FunctionComment, so the sniff does apply to tests/.

Measured across both changed PHP files, --report=source:
  merge-base 590070b : 192 violations / 31 sources
  before this commit  : 193 / 31 (FunctionComment.Missing 3 -> 4)
  after this commit   : 192 / 31, byte-identical to baseline

Author: bartech

tests/php/test-class-wc-connect-taxjar-integration.php

@@ -2261,12 +2261,6 @@ function ( $taxable, $product ) use ( $filtered_id ) {
 		WC_Helper_Product::delete_product( $filtered_id );
 	}
 
-	/**
-	 * Tax Status "Shipping only" is exempt from item tax, and the backend order path
-	 * sends it to TaxJar as exempt (code 99999) — unlike the cart path, which excludes
-	 * that status from the exempt branch. This is the input side of the zeroing bug:
-	 * an exempt code is what makes TaxJar return the 0% breakdown line.
-	 */
 	/**
 	 * Cart path: a "Shipping only" product must NOT be recorded as non-taxable.
 	 *
@@ -2347,6 +2341,12 @@ public function test_get_line_items_still_records_none_status_as_non_taxable() {
 		WC_Helper_Product::delete_product( $product->get_id() );
 	}
 
+	/**
+	 * Tax Status "Shipping only" is exempt from item tax, and the backend order path
+	 * sends it to TaxJar as exempt (code 99999) — unlike the cart path, which excludes
+	 * that status from the exempt branch. This is the input side of the zeroing bug:
+	 * an exempt code is what makes TaxJar return the 0% breakdown line.
+	 */
 	public function test_get_backend_line_items_sends_shipping_only_status_as_exempt() {
 		$product = WC_Helper_Product::create_simple_product();
 		$product->set_tax_status( 'shipping' );