doc: add document for profile and takeHeapSnapshot command of node inspect

[cola119]

Currently profile and takeHeapSnapshot command are undocumented in the debugger doc.

node/lib/internal/debugger/inspect_repl.js

Lines 104 to 111 in 0950da1

	profile Start CPU profiling session.
	profileEnd Stop current CPU profiling session.
	profiles Array of completed CPU profiling sessions.
	profiles[n].save(filepath = 'node.cpuprofile')
	Save CPU profiling session to disk as JSON.
	takeHeapSnapshot(filepath = 'node.heapsnapshot')
	Take a heap snapshot and save to disk as JSON.

[Trott]

One question about the unwatch addition....

issue resolved

[Trott]

@nodejs/documentation I think this is fine, but it does deviate from our usual docs (using default parameter syntax rather than **Default:**, although this is an unusual case and previous elements in the list already deviate from the standard approach). Since this isn't a programmatic API but an interactive REPL, I think it's fine. What do you think?