finalize changelog for Iris 3.4 release

See merge request iris/iris!639

add better lemmas for working with mask-changing fupd, and rearrange names a bit

See merge request iris/iris!637

fix monPred scope binding

See merge request iris/iris!638

Rename `equiv_spec` → `equiv_entails` to be consistent with conventions in std++.

See merge request iris/iris!628

Hence, also rename (the old) `equiv_entails` → `equiv_entails_1_1` and
`equiv_entails_sym` → `equiv_entails_1_2`, and add `equiv_entails_2` for completeness.

adapt to coq/coq#13840

See merge request iris/iris!635

rename u?frac_op/valid' to remove the final '

See merge request iris/iris!632

mostly make Iris compatible with name mangling

See merge request iris/iris!624

add "deprecated" and "staging" packages and deprecate some modules

See merge request iris/iris!602

create iris-deprecated and iris-staging packages, and deprecate some hard-to-use logic-level wrappers as well as view shift and Hoare triple notation

Fix wp_bind's error message

Closes #401

See merge request iris/iris!633

Fixes #401

Add tests for wp_load and wp_store failures

See merge request iris/iris!634

Rename monoid-related operational typeclass instances to include the suffix '_instance'

See merge request iris/iris!629

This was done using the following sed script:
sed -i -E 's/Instance ([a-zA-Z0-9_]+)( .*: (Op|P?Core|ValidN?|Unit) )/Instance \1_instance\2/' $(find iris/algebra -name "*.v")