Update wording and config

docs/sample_config.yaml

@@ -1365,6 +1365,9 @@ saml2_config:
   # If no file is provided, this defaults to some minimalistic HTML telling the
   # user that something went wrong and they should try authenticating again.
   #
+  # See https://github.com/matrix-org/synapse/blob/master/synapse/res/templates/saml_error.html
+  # for an example.
+  #
   #error_html_path: /path/to/static/content/saml_error.html
 
 

synapse/config/saml2_config.py

@@ -343,6 +343,9 @@ class SAML2Config(Config):
           # If no file is provided, this defaults to some minimalistic HTML telling the
           # user that something went wrong and they should try authenticating again.
           #
+          # See https://github.com/matrix-org/synapse/blob/master/synapse/res/templates/saml_error.html
+          # for an example.
+          #
           #error_html_path: /path/to/static/content/saml_error.html
         """ % {
             "config_dir_path": config_dir_path

synapse/res/templates/saml_error.html

@@ -24,8 +24,8 @@
         // we just don't print anything specific.
         let searchStr = "";
         if (window.location.search) {
-            // For some reason window.location.searchParams isn't always defined when
-            // window.location.search is, so we can't just use it right away.
+            // window.location.searchParams isn't always defined when
+            // window.location.search is, so it's more reliable to parse the latter.
             searchStr = window.location.search;
         } else if (window.location.hash) {
             // Replace the # with a ? so that URLSearchParams does the right thing and