docs: Annotate features requiring 2.20

We had several people confused by the docs.

Author: jtojnar

docs/content/docs/administration/options.md

@@ -82,7 +82,7 @@ number of entries per page on your stream
 ### `items_lifetime`
 <div class="config-option">
 
-Number of days since the item has been last seen after which it can be deleted. Set to `0` to disable item deletion. Starred items will never be deleted.
+Number of days since the item has been last seen after which it can be deleted. In the upcoming selfoss 2.20, you can set it to `0` to disable item deletion. Starred items will never be deleted.
 </div>
 
 ### `base_url`
@@ -196,7 +196,7 @@ set `0` or leave empty for auto detection (browser language) or use one of the f
 * Slovak: `sk`
 * Spanish: `es`
 * Swedish: `sv`
-* Tamil: `ta`
+* Tamil: `ta` (will only be available in selfoss 2.20 or later)
 * Turkish: `tr`
 * Ukrainian: `uk`
 </div>
@@ -218,7 +218,7 @@ Set to `1` to allow public access for `/update` (anybody can access and start th
 <dt><code>t</code></dt><dd>Twitter</dd>
 <dt><code>p</code></dt><dd>Pocket</dd>
 <dt><code>d</code></dt><dd>Diaspora</dd>
-<dt><code>m</code></dt><dd>Mastodon (requires <a href="#mastodon"><code>mastodon</code></a> option to be set)</dd>
+<dt><code>m</code></dt><dd>Mastodon (requires <a href="#mastodon"><code>mastodon</code></a> option to be set, will only be available in selfoss 2.20 or later)</dd>
 <dt><code>w</code></dt><dd>Wallabag (requires <a href="#wallabag"><code>wallabag</code></a> option to be set)</dd>
 <dt><code>s</code></dt><dd>Wordpress (requires <a href="#wordpress"><code>wordpress</code></a> option to be set)</dd>
 <dt><code>e</code></dt><dd>E-mail</dd>

docs/content/docs/customization/spouts/index.md

@@ -19,6 +19,14 @@ If you want to get the newest entries from your own source (e.g. an IMAP e-mail
 
 Create a new PHP file under `src/spouts/your_spouts/your_spout.php` (choose a name for `your_spouts` and `your_spout`). The easiest way is to copy the [`src/spouts/rss/feed.php`](https://github.com/fossar/selfoss/blob/master/src/spouts/rss/feed.php) and to modify this file.
 
+<div class="admonition warning">
+
+## Warning
+
+The following documentation targets the upcoming selfoss 2.20. You can read about the changes in [NEWS](https://github.com/fossar/selfoss/blob/master/NEWS.md#customization-changes).
+
+</div>
+
 ### Member Variables
 Set the `$name` and `$description` variable with the name and description of your spout. The `$params` contain the definition of the input fields which a user will have to fill to add a new source of your spout (e.g. `username` and `password` for accessing the source data).
 

docs/content/docs/project/release-checklist.md

@@ -4,6 +4,7 @@ weight = 40
 +++
 
 1. Update `NEWS.md` with highlights of changes that are not yet there. Set a release date.
+2. Revert <https://github.com/fossar/selfoss/pull/1521>.
 2. Update the version strings throughout the code base to the new release using `npm run bump-version 2.19` and commit the changes.
 3. Commit the changes.
 4. Create a tag using `git tag 2.19`.

docs/content/docs/usage/filters.md

@@ -5,6 +5,14 @@ weight = 40
 
 You can limit which items of sources will be stored in the database by specifying a filter expression in the “Filter” field of a source on the Settings page.
 
+<div class="admonition warning">
+
+## Warning
+
+The *field-specific* or *negated* filters require the upcoming selfoss 2.20. Older versions only support *atomic filters*.
+
+</div>
+
 The filter expression can take one of the following forms:
 
 1. An *atomic filter*: a Perl-compatible regular expression, as [accepted by PHP](https://www.php.net/manual/en/reference.pcre.pattern.syntax.php), between forward slashes (`/`). For example, `/reg(ular expression|ex)/` will keep only items whose title or content matches the regular expression between the slashes (i.e. contain the phrase “regular expression” or “regex”). Learn more about regular expressions on <https://www.regular-expressions.info/>.

docs/sass/style.scss

@@ -451,3 +451,24 @@ kbd {
 .footnote-definition-label {
     margin-right: 0.95rem;
 }
+
+// Admonitions
+.admonition {
+    background: #d4d4d244;
+    border-left: 0.3rem solid #d4d4d2;
+    padding: 1rem;
+    border-radius: 0.3rem;
+}
+
+.admonition h2 {
+    margin: 0;
+}
+
+.admonition.warning {
+    background: #d9770644;
+    border-left-color: #d97706;
+}
+
+.admonition.warning h2 {
+    color: #d97706;
+}