[PATCH] Fix memory leak in rb_const_remove when using namespace

	We need to free the rb_const_entry_t we remove from the RCLASS_WRITABLE_CONST_TBL
	otherwise it will leak memory.

[Bug #21438]

Previously GC could trigger a table rebuild of the generic ivar
st_table in the middle of calling the st_update callback. This could
cause entries to be reallocated or rearranged and the update to be for
the wrong entry.

This commit adds an assertion to make that case easier to detect, and
replaces the st_update with a separate st_lookup and st_insert.

Also free after insert in generic_ivar_set_shape_ivptr

Previously we were performing a realloc and then inserting the new value
into the table. If the table was flagged as requiring a rebuild, this
could trigger GC work and marking within that GC could access the ivptr
freed by realloc.

Co-authored-by: Aaron Patterson <tenderlove@ruby-lang.org>
Co-authored-by: Jean Boussier <byroot@ruby-lang.org>

	[Bug #21094] Update nested module names when setting temporary name

	[Bug #21159] module names should not be modifiable

* Reword Range#overlap? docs last paragraph.

* Docs: add explanation about Queue#freeze

* Docs: Add :rescue event docs for TracePoint

* Docs: Enhance Module#set_temporary_name documentation

* Docs: Slightly expand Process::Status deprecations

* Fix MatchData#named_captures rendering glitch

* Improve Dir.fchdir examples

* Adjust Refinement#target docs

when the RUBY_FREE_ON_SHUTDOWN environment variable is set, manually free memory at shutdown.

Co-authored-by: Nobuyoshi Nakada <nobu@ruby-lang.org>
Co-authored-by: Peter Zhu <peter@peterzhu.ca>

For this public API, the callback is declared to take
`(ID, VALUE, st_data_t)`, but it so happens that using
`(st_data_t, st_data_t, st_data_t)` also
type checks, because the underlying type is identical.
Use it as declared and get rid of some casts.