docs(fcheckout): update code doc for fcheckout

scripts/fcheckout

@@ -5,16 +5,16 @@
 # @params
 # Globals
 #   ${mydir}: current directory of the script, used for imports
-#   ${action_type}: what type of git commands to use, branch, commit files, modified files
+#   ${action_type}: what type of git commands to use (branch|select|commit|modified)
 #   ${selected_branch}: selected_branch to switch
-#   ${selected_files}: selected_files to checkout to the version in HEAD
+#   ${selected_files}: selected_files to checkout
 #   ${selected_commit}: selected commit to checkout
 #   ${confirm}: confirm status of the user
 # Arguments
-#   -h: show help message
-#   -a: search all files instead of just the modified files
-#   -b: search branch and checkout branch
-#   -c: search commit and checkout commit
+#   -h|--help: show help message
+#   -s|--select: search all files instead of just the modified files
+#   -b|--branch: search branch and checkout branch
+#   -c|--commit: search commit and checkout commit
 
 set -e
 set -f
@@ -25,14 +25,17 @@ source "${mydir}"/../helper/get_confirmation.sh
 source "${mydir}"/../helper/git_query.sh
 
 function usage() {
-  echo -e "Usage: dotbare fcheckout [-h] [-a] [-b] [-c] ...\n"
-  echo -e "Checkout files/commit/branch using fzf\n"
+  echo -e "Usage: dotbare fcheckout [-h] [-s] [-b] [-c] ...\n"
+  echo -e "Checkout files/commit/branch using fzf"
+  echo -e "files: checkout the version in HEAD or in a specific commit (reset files content back to the selected commit)"
+  echo -e "branch: switch to the selected branch"
+  echo -e "commit: switch to a specific commit\n"
   echo -e "Default: checkout files back to HEAD (Reset changes back to HEAD)\n"
   echo -e "optional arguments:"
-  echo -e "  -h\t\tshow this help message and exit"
-  echo -e "  -a\t\tsearch all files and select a commit to checkout for selected files"
-  echo -e "  -b\t\tlist all branch and checkout/switch the selected branch"
-  echo -e "  -c\t\tlist all commits and checkout selected commit"
+  echo -e "  -h, --help\t\tshow this help message and exit"
+  echo -e "  -s, --select\t\tsearch all files and select a commit to checkout for selected files"
+  echo -e "  -b, --branch\t\tlist all branch and checkout/switch the selected branch"
+  echo -e "  -c, --commit\t\tlist all commits and checkout selected commit"
 }
 
 action_type="modified"