Rework RTD URL to work with the url checker

Author: jsiirola

.github/workflows/url_check.yml

@@ -29,4 +29,4 @@ jobs:
         # Exclude:
         #  - Jenkins because it's behind a firewall
         #  - RTD because a magically-generated string triggers failures
-        exclude_urls: 'https://pyomo-jenkins.sandia.gov/,https://pyomo.readthedocs.io/en/%s/errors.html#%s'
+        exclude_urls: https://pyomo-jenkins.sandia.gov/,https://pyomo.readthedocs.io/en/%s/errors.html

pyomo/common/log.py

@@ -33,14 +33,16 @@
 
 _indentation_re = re.compile(r'\s*')
 
+_RTD_URL = "https://pyomo.readthedocs.io/en/%s/errors.html"
+
 
 def RTD(_id):
     _id = str(_id).lower()
-    assert _id[0] in 'wex'
-    return "https://pyomo.readthedocs.io/en/%s/errors.html#%s" % (
-        'stable' if (releaselevel == 'final' or in_testing_environment()) else 'latest',
-        _id,
+    _release = (
+        'stable' if releaselevel == 'final' or in_testing_environment() else 'latest'
     )
+    assert _id[0] in 'wex'
+    return (_RTD_URL % (_release,)) + f"#{_id}"
 
 
 _DEBUG = logging.DEBUG