consolidate run functions (#126)

consolidating logic for when a chain is able to run with single input
text, single output text

open to feedback on naming, logic, usefulness

tests/integration_tests/chains/test_serpapi.py

@@ -5,5 +5,5 @@ from langchain.chains.serpapi import SerpAPIChain
 def test_call() -> None:
     """Test that call gives the correct answer."""
     chain = SerpAPIChain()
-    output = chain.search("What was Obama's first name?")
+    output = chain.run("What was Obama's first name?")
     assert output == "Barack Hussein Obama II"

tests/integration_tests/chains/test_sql_database.py

@@ -25,6 +25,6 @@ def test_sql_database_run() -> None:
         conn.execute(stmt)
     db = SQLDatabase(engine)
     db_chain = SQLDatabaseChain(llm=OpenAI(temperature=0), database=db)
-    output = db_chain.query("What company does Harrison work at?")
+    output = db_chain.run("What company does Harrison work at?")
     expected_output = " Harrison works at Foo."
     assert output == expected_output