howto_release.md: more "Create tag" tricks added (#2116)

* howto_release.md: more "Create tag" tricks added
* Alternative ChangeLog generation cmd added

doc/howto_release.md

@@ -155,11 +155,14 @@ To be done in GH interface:
 <https://github.com/OSGeo/grass/releases/new>
 
 - select release_branch first, then
-- write into "Create tag" field:
+- fill in "Release Title" (e.g., GRASS GIS 8.0.0RC1)
+- fill in "Create tag" field:
 
 Tag version | target (examples):
   8.0.0RC1  | releasebranch_8_0
 
+- click on "Create new tag: ... on publish"
+
 Add release desciption (re-use existing texts as possible, from
 <https://github.com/OSGeo/grass/releases>)
 
@@ -184,7 +187,13 @@ Using GH API here, see also
 gh api repos/OSGeo/grass/releases/generate-notes -f tag_name="8.0.0" -f previous_tag_name=7.8.6 -f target_commitish=releasebranch_8_0 -q .body
 ```
 
-Importantly, these notes need to be manually sorted into the various categories.
+If this fails, also a date may be used (that of the last release):
+
+```bash
+git log --oneline --after="2021-10-10" | cut -d' ' -f2- | sed 's+^+* +g' | sed 's+(#+https://github.com/OSGeo/grass/pull/+g' | sed 's+)$++g' | sort -u
+```
+
+Importantly, these notes need to be manually sorted into the various categories (modules, wxGUI, library, docker, ...).
 
 ### Changelog file for upload
 
@@ -312,7 +321,7 @@ Software pages:
 
 #### Only in case of new major release
 
-- update cronjob '[cron_grass_HEAD_src_snapshot.sh](https://github.com/OSGeo/grass-addons/tree/grass8/utils/cronjobs_osgeo_lxd)' on grass.osgeo.org to next
+- update cronjob '[cron_grass8_main_src_snapshot.sh](https://github.com/OSGeo/grass-addons/tree/grass8/utils/cronjobs_osgeo_lxd/)' on grass.osgeo.org to next
   but one release tag for the differences
 - wiki updates, only when new major release:
     - {{cmd|xxxx}} macro: <https://grasswiki.osgeo.org/wiki/Template:Cmd>