Fix SQLAlchemy deprecation warnings

- Import text from sqlalchemy
- Wrap "SELECT 1" statements in text() function in index() and
  detail_page()
- Addresses SQLAlchemy 2.0+ requirement for explicit text() wrapper on
  raw SQL strings

lookup.py

@@ -15,7 +15,7 @@ from flask import Flask, jsonify, redirect, render_template, request, url_for
 from pygments import highlight
 from pygments.formatters import HtmlFormatter
 from pygments.lexers import SparqlLexer
-from sqlalchemy import func
+from sqlalchemy import func, text
 from sqlalchemy.orm.query import Query
 from werkzeug.wrappers import Response
 
@@ -238,7 +238,7 @@ def handle_database_error(error: Exception) -> tuple[str, int]:
 def index() -> str | Response:
     """Index page."""
     t0 = time()
-    database.session.execute("SELECT 1")
+    database.session.execute(text("SELECT 1"))
     q = request.args.get("q")
     if q and q.strip():
         return redirect_to_detail(q)
@@ -351,7 +351,7 @@ def build_detail_page(lat: float, lon: float) -> str:
 @app.route("/detail")
 def detail_page() -> Response | str:
     """Detail page."""
-    database.session.execute("SELECT 1")
+    database.session.execute(text("SELECT 1"))
     try:
         lat_str, lon_str = request.args["lat"], request.args["lon"]
         lat, lon = float(lat_str), float(lon_str)