Improve documentation of template modifiers

* Moved them to a separate page
* Improved general explanation
* Explained how to replace deprecated modifiers
* Documented whitelisted PHP functions that can be used as a variable modifier

Author: BurntimeX

docs/view/template-modifiers.md

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+# Template Modifiers
+
+Variable modifiers are used to modify the output of variables within templates.
+These modifiers allow you to perform various operations on the variables before displaying them.
+The general syntax for applying a variable modifier is `{$variable|modifier}`.
+
+Modifiers can be chained together to perform multiple operations on a variable. In such cases, the modifiers are applied from left to right. For example:
+```smarty
+{$variable|modifier1|modifier2|modifier3}
+```
+
+A modifier may accept additional parameters that affect its behavior. These parameters follow the modifier name and are separated by a `:`. For example:
+```smarty
+{$variable|modifier:'param1':'param2'}
+```
+
+## Build-in Modifiers
+
+### `|concat`
+
+`concat` is a modifier used to concatenate multiple strings:
+
+```smarty
+{assign var=foo value='foo'}
+
+{assign var=templateVariable value='bar'|concat:$foo}
+
+{$templateVariable} {* prints 'foobar *}
+```
+
+### `|currency`
+
+`currency` is a modifier used to format currency values with two decimals using language dependent thousands separators and decimal point:
+
+```smarty
+{assign var=currencyValue value=12.345}
+
+{$currencyValue|currency} {* prints '12.34' *}
+```
+
+### `|date`
+
+!!! info "This template plugin has been deprecated in WoltLab Suite 6.0. Use `{time type='plainDate'}` or `{time type='custom'}` instead."
+
+`date` generated a formatted date using `wcf\util\DateUtil::format()` with `DateUtil::DATE_FORMAT` internally.
+
+```smarty
+{$timestamp|date}
+```
+
+### `|encodeJS`
+
+`encodeJS` encodes a string to be used as a single-quoted string in JavaScript by replacing `\\` with `\\\\`, `'` with `\'`, linebreaks with `\n`, and `/` with `\/`.
+
+```smarty
+<script>
+	var foo = '{@$foo|encodeJS}';
+</script>
+```
+
+### `|escapeCDATA`
+
+`escapeCDATA` encodes a string to be used in a `CDATA` element by replacing `]]>` with `]]]]><![CDATA[>`.
+
+```smarty
+<![CDATA[{@$foo|encodeCDATA}]]>
+```
+
+
+### `|filesizeBinary`
+
+`filesizeBinary` formats the filesize using binary filesize (in bytes).
+
+```smarty
+{$filesize|filesizeBinary}
+```
+
+
+### `|filesize`
+
+`filesize` formats the filesize using filesize (in bytes).
+
+```smarty
+{$filesize|filesize}
+```
+
+### `|ipSearch`
+
+`ipSearch` generates a link to search for an IP address.
+
+```smarty
+{"127.0.0.1"|ipSearch}
+```
+
+### `|json`
+
+`json` JSON-encodes the given value.
+
+```smarty
+<script>
+let data = { "title": {@$foo->getTitle()|json} };
+</script>
+```
+
+### `|language`
+
+`language` replaces a language items with its value.
+If the template variable `__language` exists, this language object will be used instead of `WCF::getLanguage()`.
+This modifier is useful when assigning the value directly to a variable.
+
+Note that template scripting is applied to the output of the variable, which can lead to unwanted side effects. Use `phrase` instead if you don't want to use template scripting.
+
+```smarty
+{$languageItem|language}
+
+{assign var=foo value=$languageItem|language}
+```
+
+### `|newlineToBreak`
+
+`newlineToBreak` transforms newlines into HTML `<br>` elements after encoding the content via `wcf\util\StringUtil::encodeHTML()`.
+
+```smarty
+{$foo|newlineToBreak}
+```
+
+### `|phrase`
+
+`phrase` replaces a language items with its value.
+If the template variable `__language` exists, this language object will be used instead of `WCF::getLanguage()`.
+This modifier is useful when assigning the value directly to a variable.
+
+`phrase` should be used instead of `language` unless you want to explicitly allow template scripting on a variable's output.
+
+```smarty
+{$languageItem|phrase}
+
+{assign var=foo value=$languageItem|phrase}
+```
+
+### `|plainTime`
+
+!!! info "This template plugin has been deprecated in WoltLab Suite 6.0. Use `{time type='plainTime'}` instead."
+
+`plainTime` formats a timestamp to include year, month, day, hour, and minutes.
+The exact formatting depends on the current language (via the language items `wcf.date.dateTimeFormat`, `wcf.date.dateFormat`, and `wcf.date.timeFormat`).
+
+```smarty
+{$timestamp|plainTime}
+```
+
+### `|shortUnit`
+
+`shortUnit` shortens numbers larger than 1000 by using unit suffixes:
+
+```smarty
+{10000|shortUnit} {* prints 10k *}
+{5400000|shortUnit} {* prints 5.4M *}
+```
+
+
+### `|tableWordwrap`
+
+`tableWordwrap` inserts zero width spaces every 30 characters in words longer than 30 characters.
+
+```smarty
+{$foo|tableWordwrap}
+```
+
+### `|time`
+
+!!! info "This template plugin has been deprecated in WoltLab Suite 6.0. Use `{time}` instead."
+
+`time` generates an HTML `time` elements based on a timestamp that shows a relative time or the absolute time if the timestamp more than six days ago.
+
+```smarty
+{$timestamp|time} {* prints a '<time>' element *}
+```
+
+
+### `|truncate`
+
+`truncate` truncates a long string into a shorter one:
+
+```smarty
+{$foo|truncate:35}
+
+{$foo|truncate:35:'_':true}
+```
+
+
+| Parameter Number | Description |
+|-----------|-------------|
+| 0 | truncated string |
+| 1 | truncated length; `80` by default |
+| 2 | ellipsis symbol; `wcf\util\StringUtil::HELLIP` by default |
+| 3 | if `true`, words can be broken up in the middle; `false` by default |
+
+
+## PHP Functions
+
+A whitelisted set of PHP functions can also be used as variable modifiers:
+
+* `abs`
+* `addslashes`
+* `array_diff`
+* `array_fill`
+* `array_key_exists`
+* `array_keys`
+* `array_pop`
+* `array_slice`
+* `array_values`
+* `base64_decode`
+* `base64_encode`
+* `basename`
+* `ceil`
+* `concat`
+* `constant`
+* `count`
+* `currency`
+* `current`
+* `date`
+* `defined`
+* `doubleval`
+* `empty`
+* `end`
+* `explode`
+* `file_exists`
+* `filesize`
+* `floatval`
+* `floor`
+* `function_exists`
+* `get_class`
+* `gmdate`
+* `hash`
+* `htmlspecialchars`
+* `html_entity_decode`
+* `http_build_query`
+* `implode`
+* `in_array`
+* `is_array`
+* `is_null`
+* `is_numeric`
+* `is_object`
+* `is_string`
+* `iterator_count`
+* `intval`
+* `is_subclass_of`
+* `isset`
+* `json_encode`
+* `key`
+* `lcfirst`
+* `ltrim`
+* `max`
+* `mb_strpos`
+* `mb_strlen`
+* `mb_strpos`
+* `mb_strtolower`
+* `mb_strtoupper`
+* `mb_substr`
+* `md5`
+* `method_exists`
+* `microtime`
+* `min`
+* `nl2br`
+* `number_format`
+* `parse_url`
+* `preg_match`
+* `preg_replace`
+* `print_r`
+* `random_int`
+* `rawurlencode`
+* `reset`
+* `round`
+* `sha1`
+* `spl_object_hash`
+* `sprintf`
+* `strip_tags`
+* `strlen`
+* `strpos`
+* `strtolower`
+* `strtotime`
+* `strtoupper`
+* `str_contains`
+* `str_ends_with`
+* `str_ireplace`
+* `str_pad`
+* `str_repeat`
+* `str_replace`
+* `str_starts_with`
+* `substr`
+* `trim`
+* `ucfirst`
+* `uniqid`
+* `urlencode`
+* `var_dump`
+* `version_compare`
+* `wcfDebug`
+* `wordwrap`