Rename hrex rbfe entry point function

Clarify that this is a 2-step hybrid of bisection followed by hrex

tests/hrex/test_hrex_alchemical.py

@@ -5,7 +5,7 @@
 import pytest
 
 from timemachine.fe.free_energy import HostConfig, MDParams
-from timemachine.fe.rbfe import estimate_relative_free_energy_hrex
+from timemachine.fe.rbfe import estimate_relative_free_energy_bisection_hrex
 from timemachine.ff import Forcefield
 from timemachine.md import builders
 from timemachine.testsystems.relative import get_hif2a_ligand_pair_single_topology
@@ -32,7 +32,7 @@ def test_hrex_rbfe_hif2a(host: Optional[str]):
         box += np.diag([0.1, 0.1, 0.1])  # remove any possible clashes
         host_config = HostConfig(host_sys, host_conf, box, host_conf.shape[0])
 
-    result = estimate_relative_free_energy_hrex(
+    result = estimate_relative_free_energy_bisection_hrex(
         mol_a,
         mol_b,
         core,

tests/test_relative_free_energy.py

@@ -12,7 +12,7 @@
     DEFAULT_MD_PARAMS,
     estimate_relative_free_energy,
     estimate_relative_free_energy_bisection,
-    estimate_relative_free_energy_hrex,
+    estimate_relative_free_energy_bisection_hrex,
     run_solvent,
     run_vacuum,
 )
@@ -154,7 +154,7 @@ def check_pair_bar_result(res: PairBarResult):
     [
         estimate_relative_free_energy,
         estimate_relative_free_energy_bisection,
-        estimate_relative_free_energy_hrex,
+        estimate_relative_free_energy_bisection_hrex,
     ],
 )
 def test_run_hif2a_test_system(estimate_relative_free_energy_fn):
@@ -183,7 +183,7 @@ def test_run_hif2a_test_system(estimate_relative_free_energy_fn):
         estimate_relative_free_energy,
         estimate_relative_free_energy_bisection,
         pytest.param(
-            estimate_relative_free_energy_hrex,
+            estimate_relative_free_energy_bisection_hrex,
             marks=pytest.mark.xfail(
                 reason="lambda window trajectories are not individually reproducible given InitialState due to mixing"
             ),
@@ -415,4 +415,4 @@ def test_estimate_free_energy_bisection_invalid_args():
     # toggling the pytest marker
     test_run_hif2a_test_system(estimate_relative_free_energy)
     test_run_hif2a_test_system(estimate_relative_free_energy_bisection)
-    test_run_hif2a_test_system(estimate_relative_free_energy_hrex)
+    test_run_hif2a_test_system(estimate_relative_free_energy_bisection_hrex)

timemachine/fe/rbfe.py

@@ -585,7 +585,7 @@ def estimate_relative_free_energy_bisection(
         raise err
 
 
-def estimate_relative_free_energy_hrex(
+def estimate_relative_free_energy_bisection_hrex(
     mol_a: Chem.rdchem.Mol,
     mol_b: Chem.rdchem.Mol,
     core: NDArray,