Add help and license terms to sources/*

To:
- sources/alias_of.sh
- sources/cd-finddir.sh
- sources/cd-to-git-root.sh
- sources/cd-to-node-root.sh
- sources/contains_value.sh
- sources/force-unexport.sh
- sources/i_have.sh
- sources/is_array.sh
- sources/load-my-env.sh
- sources/source_if_exists.sh

Author: aiya000

sources/alias_of.sh

@@ -1,8 +1,7 @@
 #!/bin/bash
 
-# If $1 exists, create an alias for $1 with the contents of $2 and overwrite it.
+# If `$1` exists, create an alias for `$1` with the contents of `$2` and overwrite it.
 #
-# Example:
 # ```shell-session
 # $ alias_of rg 'rg --color always --hidden'
 # $ alias rg

sources/cd-finddir.sh

@@ -1,8 +1,10 @@
 #!/bin/bash
 
-#
 # Shows all directories of 6 depth (if `fd` is available, or 3 depth for `find`), and cd to a directory you selected.
 #
+# ```shell-session
+# TODO: Write an example
+# ```
 
 dir="$(cd -- "$(dirname -- "${BASH_SOURCE:-$0}")" && pwd || exit 1)"
 

sources/cd-to-git-root.sh

@@ -1,11 +1,11 @@
 #!/bin/bash
 
+# `cd` to the git root directory.
+# The behavior when Atata is on a Windows file system with WSL is also supported.
 #
-# `cd` to the git root directory
-# With `wslpath` support.
-# Try using `wslpath`.
-# This is often useful if you are in a git directory of Windows filesystem.
-#
+# ```shell-session
+# TODO: Write an example
+# ```
 
 function cd-to-git-root () {
   local root

sources/cd-to-node-root.sh

@@ -1,8 +1,10 @@
 #!/bin/bash
 
+# `cd` to a directory that have a `package.json`.
 #
-# cd to a directory that have a package.json.
-#
+# ```shell-session
+# TODO: Write an example
+# ```
 
 function cd-to-node-root::find-node-root-dir () {
   local current_dir=$1

sources/contains_value.sh

@@ -1,7 +1,5 @@
 #!/bin/bash
 
-# Example
-#
 # ```bash
 # target=banana
 # my_array=(apple banana cherry)

sources/force-unexport.sh

@@ -1,11 +1,11 @@
 #!/bin/bash
 
-# Example:
-#
+# ```shell-session
 # $ export FOO=1
 # $ force-unexport FOO
 # $ [[ -z $FOO ]] && echo yes
 # yes
+# ```
 #
 # See: https://unix.stackexchange.com/questions/252747/how-can-i-un-export-a-variable-without-losing-its-value
 

sources/i_have.sh

@@ -2,8 +2,6 @@
 
 # A shorthand to check a specified command does exist or not.
 #
-# Example:
-#
 # ```bash
 # if i_have batcat ; then
 #   alias bat=batcat

sources/is_array.sh

@@ -1,8 +1,7 @@
 #!/bin/bash
 
-# Check a taken var name is an array
+# Checks a taken var name is an array.
 #
-# Example:
 # ```shell-session
 # $ foo=()
 # $ is_array foo && echo yes || echo no

sources/load-my-env.sh

@@ -1,5 +1,11 @@
 #!/bin/bash
 
+# TODO: Add the help and the description.
+#
+# ```shell-session
+# TODO: Write an example
+# ```
+
 function load-my-env () {
   local target_name="$1"
 

sources/source_if_exists.sh

@@ -1,5 +1,11 @@
 #!/bin/bash
 
+# TODO: Add the help and the description.
+#
+# ```shell-session
+# TODO: Write an example
+# ```
+
 function source_if_exists () {
   if [[ -f $1 ]] ; then
     # shellcheck disable=SC1090