Fix inability to edit, delete (etc.) help topics whose names overlap non-db topic names.

[chiizujin]

Brief overview of PR changes/additions

When database help topics are created with a name that overlaps a non-database help topic, the database topic can no longer be edited in any way, including deletion.

Motivation for adding to Evennia

Bug fix.

Other info

Before:

>sethelp ban = Test.
Warning:
'ban' matches (or partially matches) the key/alias of Command 'ban'.
Command-help take precedence over other help entries so your help *may* be
impossible to reach for those with access to that command.
Do you still want to continue? Y/[N]?
>y
Topic 'ban' was successfully created.

>sethelp/replace ban = Test 2.
Warning:
'ban' matches (or partially matches) the key/alias of Command 'ban'.
Command-help take precedence over other help entries so your help *may* be
impossible to reach for those with access to that command.
Do you still want to continue? Y/[N]?
>y
Error when creating topic 'ban'! Contact an admin.

After:

>sethelp ban = Test.
Warning:
'ban' matches (or partially matches) the key/alias of Command 'ban'.
Command-help take precedence over other help entries so your help *may* be
impossible to reach for those with access to that command.
Do you still want to continue? Y/[N]?
>y
Topic 'ban' was successfully created.

>sethelp/replace ban = Test 2.
Warning:
'ban' matches (or partially matches) the key/alias of Command 'ban'.
Command-help take precedence over other help entries so your help *may* be
impossible to reach for those with access to that command.
Do you still want to continue? Y/[N]?
>y
Overwrote the old topic 'ban'.

>sethelp/edit ban
Warning:
'ban' matches (or partially matches) the key/alias of Command 'ban'.
Command-help take precedence over other help entries so your help *may* be
impossible to reach for those with access to that command.
Do you still want to continue? Y/[N]?
>y
----------Line Editor [topic ban]---------------------------------------------
01| Test 2.
----------[l:01 w:002 c:0007]------------(:h for help)------------------------

[Griatch]

An edge case, but an annoying one!