Berry debug.caller

[s-hadinger]

Description:

Berry add debug.caller() to get the functions from the calling hierarchy.

Sync from berry-lang/berry#390

debug.caller()with the following semantics:

• debug.caller(nil) -> function or nil return current function
• debug.caller(int) -> function or nil return the nth caller in chain (default is 1).

One typical use-case is to get the name of the current function, or the name of the caller function. Note: use introspect.name() to get the name of a function.

Example:

def guess_my_name()
    import debug
    import introspect
    var func = debug.caller()
    var func_name = introspect.name(func)
    print(func_name)
end
guess_my_name()
# prints: guess_my_name

Checklist:

• The pull request is done against the latest development branch
• Only relevant files were touched
• Only one feature/fix was added per PR and the code change compiles without warnings
• The code change is tested and works with Tasmota core ESP8266 V.2.7.5
• The code change is tested and works with Tasmota core ESP32 V.2.0.14
• I accept the CLA.

NOTE: The code change must pass CI tests. Your PR cannot be merged unless tests pass