scripts: west_commands: completion: Add hwmv2 complete to fish

Adds hwmv2 board completetion support to fish

Signed-off-by: Jamie McCrae <jamie.mccrae@nordicsemi.no>

scripts/west_commands/completion/west-completion.fish

@@ -196,11 +196,21 @@ function __zephyr_west_complete_help
 end
 
 function __zephyr_west_complete_board
+    # HWMv1
     set -l boards (west 2>/dev/null boards --format="{name} {arch}")
     for board in $boards
         set -l b (string split " " $board)
         printf "%s\n" $b[1]\t"$b[2]"
     end
+
+    # HWMv2
+    set -l boards (west 2>/dev/null boards --format="{identifiers}")
+    for board in $boards
+        set -l b (string split "," $board)
+        for variant in $b
+            printf "%s\n" $variant[1]
+        end
+    end
 end
 
 # disable file completion, if an option need it, it should use '--force-files'