docs: fix grammar in tests/istanbul and tests/berlin

repo_subpaths_for_grammar_check.md

@@ -16,7 +16,7 @@ Status legend: `[ ]` pending, `[~]` in progress, `[x]` complete
 - [x] `tests/json_infra/**/*.py` (~22 files)
 - [x] `tests/shanghai/**/*.py` (~19 files)
 - [x] `tests/byzantium/**/*.py` (~11 files)
-- [ ] `tests/istanbul/**/*.py`, `berlin/**/*.py` (~18 files)
+- [x] `tests/istanbul/**/*.py`, `berlin/**/*.py` (~18 files)
 - [ ] `tests/constantinople/**/*.py`, `amsterdam/**/*.py` (~16 files)
 - [ ] `tests/london/**/*.py`, `homestead/**/*.py`, `paris/**/*.py` (~17 files)
 - [ ] `tests/*.py`, `tests/common/**/*.py`, `tests/evm_tools/**/*.py` (~5 files)

tests/berlin/eip2929_gas_cost_increases/test_precompile_warming.py

@@ -103,7 +103,7 @@ def test_precompile_warming(
     pre: Alloc,
 ) -> None:
     """
-    Call BALANCE of a precompile addresses before and after a fork.
+    Call BALANCE of precompile addresses before and after a fork.
 
     According to EIP-2929, when a transaction begins, accessed_addresses is
     initialized to include:

tests/istanbul/eip152_blake2/test_blake2_delegatecall.py

@@ -1,5 +1,5 @@
 """
-Test delegatecall to Blake2B Precompile before and after added.
+Test delegatecall to Blake2B Precompile before and after being added.
 """
 
 import pytest