Temporary solution

suppress undefined function error
Add examples

eldoc-current-symbol
eldoc-symbol-function
face-attribute
face-all-attributes
list
Update test

Add ex-insert-current-buffer test
Update document

Add email address
Update docstring
Change ex-hash-keys argument
Add dependency: cl-lib

mv ex-before-def -> ex--before-def
Fix typo
Update examples
Add examples

eldoc-current-symbol
eldoc-symbol-function
face-attribute
face-all-attributes
list
cl-mapl
-map-when
--map-when
-map-indexed
--map-indexed
json-read-from-string
json-encode
Add ex-exec-all-examples function