#825: audited and made SDIFF docs consistent | added build fail fix ( Echo doc error )

[rishavvajpayee]

changes

This PR updates the documentation for the SDIFF command in DiceDB to improve clarity, consistency, and structure. Key changes include: ( this takes reference from the SET documentation )

• The return values and Parameters are replaced with a detailed conditions table for successful and error scenarios and paramters with types.
• Commands written in examples are now displayed in the bash instead of plan text. with defined127.0.0.1:7379> as prefix.
• Overall structure and headings were audited to match the flow of SET Documentation
• The build error in Echo due to InvalidContentEntryFormatterError was resolved. Added 'the' before teh ECHO as a fix. Any other changes in the Echo files were due to formatter.