add --man flag for man page generation

add Taskfile.man.yml
include it in the main Taskfile

add man flag to Flags section in README

Taskfile.yml

@@ -1,5 +1,8 @@
 version: '3'
 
+includes:
+  man: Taskfile.man.yml
+
 vars:
   PROGRAM: vbantxt
   SHELL: '{{if eq .OS "Windows_NT"}}powershell{{end}}'
@@ -19,14 +22,14 @@ tasks:
 
   build:
     desc: 'Build the vbantxt project'
-    deps: [vet]
+    deps: [ vet ]
     cmds:
       - task: build-windows
       - task: build-linux
       - task: build-macos
   vet:
     desc: Vet the code
-    deps: [fmt]
+    deps: [ fmt ]
     cmds:
       - go vet ./...
 
@@ -38,19 +41,22 @@ tasks:
   build-windows:
     desc: Build the vbantxt project for Windows
     cmds:
-      - GOOS=windows GOARCH=amd64 go build -o {{.WINDOWS}} -ldflags="-X main.version={{.VERSION}}" ./cmd/{{.PROGRAM}}/
+      - GOOS=windows GOARCH=amd64 go build -o {{.WINDOWS}} -ldflags="-X
+        main.version={{.VERSION}}" ./cmd/{{.PROGRAM}}/
     internal: true
 
   build-linux:
     desc: Build the vbantxt project for Linux
     cmds:
-      - GOOS=linux GOARCH=amd64 go build -o {{.LINUX}} -ldflags="-X main.version={{.VERSION}}" ./cmd/{{.PROGRAM}}/
+      - GOOS=linux GOARCH=amd64 go build -o {{.LINUX}} -ldflags="-X
+        main.version={{.VERSION}}" ./cmd/{{.PROGRAM}}/
     internal: true
 
   build-macos:
     desc: Build the vbantxt project for macOS
     cmds:
-      - GOOS=darwin GOARCH=amd64 go build -o {{.MACOS}} -ldflags="-X main.version={{.VERSION}}" ./cmd/{{.PROGRAM}}/
+      - GOOS=darwin GOARCH=amd64 go build -o {{.MACOS}} -ldflags="-X
+        main.version={{.VERSION}}" ./cmd/{{.PROGRAM}}/
     internal: true
 
   test: