[FEAT]Expand code link added

[chinma-yyy]

Issue(s)

closes #26

Acceptance Criteria fulfillment

• [x] Expand code link on recieving a github code link in the rocket chat message

Proposed changes (including videos or screenshots)

So if the text contains code link then the checkPreMessageSentExtend first checks for the github link then executePreMessageSentExtend checks whether the link is of code link. The structure is like this because for #27 and #28 we can have similar checks in executePreMessageSentExtend. Then the handleCode link adds the attachment to the message.

Further comments

[chinma-yyy]

Hey @samad-yar-khan this pr is ready for a review.