Rmk184 fix see and tedit non-extension defaults

[rmkaplan]

Fixes glitch identified in #2598 discussion

[pamoroso]

It works with no issues on Linux Mint 22.1 Cinnamon.

[pamoroso]

At commit 1131ebe I haven't found any issues.

[nbriggs]

Looking at what was done, I see --

GITFNS:
    GIT-CD-LABELFN -
	use CDVALUE from USERDATA ALIST argument instead of using CDVALUE freely
	(introduces unused binding for POS in LET)

COMPARESOURCES:
	Use better default title on CSBROWSER window
	
COMPAREDIRECTORIES
	Change USERDATA structure from PLIST to ALIST and fix usage in
	CD.COMMANDSELECTEDFN, CDFILES

	Fix INCLUDES handling to default to "" instead of NIL ... ?

	reprint modified functions and CD-MENUFN with lowercase keywords.

TEDIT-STREAM
	Improve handling of trailing/no trailing dot for signifying
	no extension or default to one of *TEDIT-EXTENSIONS*