contrib/subtree: rename .txt to .adoc

The .txt extensions were changed to .adoc in 1f010d6 (doc: use .adoc
extension for AsciiDoc files, 2025-01-20).

Do the same for contrib/subtree.

Signed-off-by: Todd Zullinger <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: tmzullinger

contrib/subtree/Makefile

@@ -50,7 +50,7 @@ GIT_SUBTREE    := git-subtree
 
 GIT_SUBTREE_DOC := git-subtree.1
 GIT_SUBTREE_XML := git-subtree.xml
-GIT_SUBTREE_TXT := git-subtree.txt
+GIT_SUBTREE_TXT := git-subtree.adoc
 GIT_SUBTREE_HTML := git-subtree.html
 GIT_SUBTREE_TEST := ../../git-subtree
 

contrib/subtree/git-subtree.txt renamed to contrib/subtree/git-subtree.adoc

@@ -32,7 +32,7 @@ if get_option('docs').contains('man')
       '@INPUT@',
     ],
     depends: documentation_deps,
-    input: 'git-subtree.txt',
+    input: 'git-subtree.adoc',
     output: 'git-subtree.xml',
   )
 
@@ -63,7 +63,7 @@ if get_option('docs').contains('html')
       '@INPUT@',
     ],
     depends: documentation_deps,
-    input: 'git-subtree.txt',
+    input: 'git-subtree.adoc',
     output: 'git-subtree.html',
     install: true,
     install_dir: get_option('datadir') / 'doc/git-doc',