Refactor echo signature to support echo multiple values

[pearmini]

@yiyujin Jin mentioned some inconsistency with echo and console.log:

//➜ "a"
echo("a", "b", "c");

console.log("a", "b", "c"); // a b c

This is because the actual signature of echo is echo(value, formatOptions). Although you can use string concatenation to achieve the similar result:

//➜ "a b c"
echo("a" + " b" + " c");

But it's inconvenient and also confusing for the user who is familiar with console.log. Also, it uses the built-in stringfy behavior which may work unexpected:

//➜ "array [, 1, 2, 3]" 
echo("array " + [null, 1, 2, 3])

So it's better update the echo signature to echo(...values). In addition to that, we also expose an extra helper function recho.inspect(value, options) for custom formatting:

//➜ "a b c"
echo("a" , "b", "c");

//➜ {                 
//➜   key: [ 1, 2, 3 ]
//➜ }                 
echo(recho.inspect({key: [1, 2, 3]}, {indent: 2}));

//➜ Peter:  Age = 20    
//➜         Height = 180
echo("Peter: ", "Age = 20\nHeight = 180");

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[Copilot]

Pull Request Overview

This PR refactors the echo function signature to support echoing multiple values in a single call, while maintaining backward compatibility for single-value usage. The key changes include moving inspector options to a dedicated recho.inspect() function and implementing horizontal merging of multiple values.

• Refactored echo function to accept multiple arguments (...values) instead of (value, options)
• Added new recho.inspect() function to handle formatting options previously passed to echo
• Updated all existing code to use recho.inspect() when formatting options are needed

Reviewed Changes

Copilot reviewed 15 out of 15 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
runtime/index.js	Core implementation of multi-value echo with horizontal merging logic
runtime/inspect.js	New inspector module with formatting functionality
runtime/stdlib.js	Export new inspect functions
test/js/echo-multiple-values.js	Test cases for multiple value echoing
test/output/echoMultipleValues.js	Expected output for multiple value tests
app/docs/*.recho.js	Documentation updates showing new API usage
app/examples/*.recho.js	Example updates to use new recho.inspect() syntax

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