feat: pretty-print JSONL text responses in mcpcurl

[simondanielsson]

This PR adds functionality to pretty-print JSONL text responses.

• Required to be able to preview response of for instance list_pull_requests.

Closes: #238

Before change:

$ ./mcpcurl --stdio-server-cmd "./github-mcp-server stdio" tools list_pull_requests --owner github --repo github-mcp-server --page 1 --perPage 1 --pretty
error printing response: failed to parse text content: json: cannot unmarshal array into Go value of type map[string]interface {}

After change:

$ ./mcpcurl --stdio-server-cmd "./github-mcp-server stdio" tools list_pull_requests --owner github --repo github-mcp-server --page 1 --perPage 1 --pretty
[
  {
    "_links": {
      "comments": {
        "href": "https://api.github.com/repos/github/github-mcp-server/issues/235/comments"
      },
      "commits": {
        "href": "https://api.github.com/repos/github/github-mcp-server/pulls/235/commits"
      },
      "html": {
        "href": "https://github.com/github/github-mcp-server/pull/235"
      },
      "issue": {
        "href": "https://api.github.com/repos/github/github-mcp-server/issues/235"
      },
      "review_comment": {
        "href": "https://api.github.com/repos/github/github-mcp-server/pulls/comments{/number}"
      },
      "review_comments": {
        "href": "https://api.github.com/repos/github/github-mcp-server/pulls/235/comments"
      },
      "self": {
        "href": "https://api.github.com/repos/github/github-mcp-server/pulls/235"
      },
      "statuses": {
        "href": "https://api.github.com/repos/github/github-mcp-server/statuses/908e3b05fab6777cf3aae284896a61d3b727c844"
      }
    },
    "author_association": "CONTRIBUTOR",
    ...

[juruen]

@simondanielsson thank you so much for your contributions! It's great to see them coming.

This looks great. I just have one stylistic suggestion to have an early continue. But otherwise, this is awesome to see!

[simondanielsson]

Thanks @juruen, great suggestion :)

[juruen]

Awesome! Thank you so much! 🚀