[INLONG-4758][Doc] Remove leading $ sign in README.md

[boatrainlsz]

• Fixes [Improve][Doc] Command-line codes in README should remove the leading $ sign #4758

Motivation

In convenience of coping and pasting for users, command line codes in READEME should remove leading $ sign. take kafka for example, there is no leading $ sign before the codes in kafka READEME.md

Modifications

Removed leading $ sign in README.md

Verifying this change

(Please pick either of the following options)

• This change is a trivial rework/code cleanup without any test coverage.

• This change is already covered by existing tests, such as:
  (please describe tests)

• This change added tests and can be verified as follows:

  (example:)

  • Added integration tests for end-to-end deployment with large payloads (10MB)
  • Extended integration test for recovery after broker failure

Documentation

• Does this pull request introduce a new feature? (yes / no)
• If yes, how is the feature documented? (not applicable / docs / JavaDocs / not documented)
• If a feature is not applicable for documentation, explain why?
• If a feature is not documented yet in this PR, please create a follow-up issue for adding the documentation

[github-actions]

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[healchow]

LGTM

[dockerzhang]

@boatrainlsz thanks.
1, do not need open and close PR when you update the commit.
2, "$" means normal users can execute this command. we can merge it for a convenient ‘copy’.

[boatrainlsz]

@boatrainlsz thanks. 1, do not need open and close PR when you update the commit. 2, "$" means normal users can execute this command. we can merge it for a convenient ‘copy’.

thanks for your advice