Add command to install shell completion (#309)

add autocompletion files to contrib/

curl -o contrib/autocomplete.zsh https://raw.githubusercontent.com/urfave/cli/master/autocomplete/zsh_autocomplete
curl -o contrib/autocomplete.sh https://raw.githubusercontent.com/urfave/cli/master/autocomplete/bash_autocomplete
add powershell

add `tea meta autocomplete`

closes #86

update docs

Co-authored-by: Norwin Roosen <git@nroo.de>
Reviewed-on: https://gitea.com/gitea/tea/pulls/309
Reviewed-by: Lunny Xiao <xiaolunwen@gmail.com>
Reviewed-by: 6543 <6543@obermui.de>
Co-Authored-By: Norwin <noerw@noreply.gitea.io>
Co-Committed-By: Norwin <noerw@noreply.gitea.io>

contrib/autocomplete.ps1

@@ -0,0 +1,9 @@
+$fn = $($MyInvocation.MyCommand.Name)
+$name = $fn -replace "(.*)\.ps1$", '$1'
+Register-ArgumentCompleter -Native -CommandName $name -ScriptBlock {
+     param($commandName, $wordToComplete, $cursorPosition)
+     $other = "$wordToComplete --generate-bash-completion"
+         Invoke-Expression $other | ForEach-Object {
+            [System.Management.Automation.CompletionResult]::new($_, $_, 'ParameterValue', $_)
+         }
+ }

contrib/autocomplete.sh

@@ -0,0 +1,21 @@
+#! /bin/bash
+
+: ${PROG:=$(basename ${BASH_SOURCE})}
+
+_cli_bash_autocomplete() {
+  if [[ "${COMP_WORDS[0]}" != "source" ]]; then
+    local cur opts base
+    COMPREPLY=()
+    cur="${COMP_WORDS[COMP_CWORD]}"
+    if [[ "$cur" == "-"* ]]; then
+      opts=$( ${COMP_WORDS[@]:0:$COMP_CWORD} ${cur} --generate-bash-completion )
+    else
+      opts=$( ${COMP_WORDS[@]:0:$COMP_CWORD} --generate-bash-completion )
+    fi
+    COMPREPLY=( $(compgen -W "${opts}" -- ${cur}) )
+    return 0
+  fi
+}
+
+complete -o bashdefault -o default -o nospace -F _cli_bash_autocomplete $PROG
+unset PROG

contrib/autocomplete.zsh

@@ -0,0 +1,23 @@
+#compdef $PROG
+
+_cli_zsh_autocomplete() {
+
+  local -a opts
+  local cur
+  cur=${words[-1]}
+  if [[ "$cur" == "-"* ]]; then
+    opts=("${(@f)$(_CLI_ZSH_AUTOCOMPLETE_HACK=1 ${words[@]:0:#words[@]-1} ${cur} --generate-bash-completion)}")
+  else
+    opts=("${(@f)$(_CLI_ZSH_AUTOCOMPLETE_HACK=1 ${words[@]:0:#words[@]-1} --generate-bash-completion)}")
+  fi
+
+  if [[ "${opts[1]}" != "" ]]; then
+    _describe 'values' opts
+  else
+    _files
+  fi
+
+  return
+}
+
+compdef _cli_zsh_autocomplete $PROG