Makefile: stop including "GIT-VERSION-FILE" in docs

We include "GIT-VERSION-FILE" in our docs Makefile, but don't actually
use the "GIT_VERSION" variable that it provides. This is a leftover from
the conversion to make "GIT-VERSION-GEN" generate version information
in-place by substituting placeholders in 4838dea (Makefile: refactor
GIT-VERSION-GEN to be reusable, 2024-12-06) and subsequent commits,
where all usages of the variable were removed.

Stop including the file.

Signed-off-by: Patrick Steinhardt <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: pks-t

Documentation/Makefile

@@ -276,13 +276,6 @@ install-pdf: pdf
 install-html: html
 	'$(SHELL_PATH_SQ)' ./install-webdoc.sh $(DESTDIR)$(htmldir)
 
-../GIT-VERSION-FILE: FORCE
-	$(QUIET_SUBDIR0)../ $(QUIET_SUBDIR1) GIT-VERSION-FILE
-
-ifneq ($(filter-out lint-docs clean,$(MAKECMDGOALS)),)
--include ../GIT-VERSION-FILE
-endif
-
 mergetools_txt = mergetools-diff.txt mergetools-merge.txt
 
 #