Allow underscores in the Windows installation path. Fixes #5467

docs/en_US/release_notes_5_1.rst

@@ -19,5 +19,6 @@ Bug fixes
 
 | `Issue #4959 <https://redmine.postgresql.org/issues/4959>`_ -  Fixed an issue where the properties tab for collection nodes is unresponsive after switching the tabs.
 | `Issue #5073 <https://redmine.postgresql.org/issues/5073>`_ -  Fixed an issue where the Save button is enabled for functions/procedures by default when open the properties dialog.
+| `Issue #5467 <https://redmine.postgresql.org/issues/5467>`_ -  Allow underscores in the Windows installation path.
 | `Issue #6018 <https://redmine.postgresql.org/issues/6018>`_ -  Fixed encoding issue when database encoding set to SQL_ASCII and name of the column is in ASCII character.
 | `Issue #6159 <https://redmine.postgresql.org/issues/6159>`_ -  Ensure that the user should be able to kill the session from Dashboard if the user has a 'pg_signal_backend' role.

pkg/win32/installer.iss.in

@@ -161,7 +161,7 @@ begin
     for I := 3 to Length(Path) do
       begin
         case Path[I] of
-          '0'..'9', 'A'..'Z', '\', ' ', '.', '-', '(', ')':
+          '0'..'9', 'A'..'Z', '\', ' ', '.', '-', '_', '(', ')':
           else
           begin
             Ret := False;