Add markup docs Str filters

markup/filters/str.md

@@ -0,0 +1,75 @@
+# Strings
+
+Winter CMS provides Twig filters for working with strings. These filters are identical to the global PHP helper functions that are documented in [Helpers > Strings](../../docs/services/helpers#strings) section.
+
+## camel
+
+The `camel` filter converts the given string to camelCase:
+
+```twig
+{{ 'test test'|camel }}
+
+{# testTest #}
+```
+
+## finish
+
+The `finish` filter adds a single instance of the given value to a string:
+
+```twig
+{{ 'test'|finish('/') }}
+
+{# test/ #}
+```
+
+## plural
+
+The `plural` filter converts a string to its plural form. This filter currently only supports the English language:
+
+```twig
+{{ 'test'|plural }}
+
+{# tests #}
+```
+
+## singular
+
+The `singular` filter converts a string to its singular form. This filter currently only supports the English language:
+
+```twig
+{{ 'letters'|singular }}
+
+{# letter #}
+```
+
+## slug
+
+The `slug` filter generates a URL friendly "slug" from the given string:
+
+```twig
+{{ 'test test'|slug }} {# test-test #}
+
+{{ 'test_test'|slug }} {# test-test #}
+
+{{ 'test test'|slug('+') }} {# test+test #}
+```
+
+## snake
+
+The `snake` filter converts the given string to snake_case:
+
+```twig
+{{ 'test test'|snake }}
+
+{# test_test #}
+```
+
+## studly
+
+The `studly` filter converts the given string to StudlyCase:
+
+```twig
+{{ 'test test'|studly }}
+
+{# TestTest #}
+```

markup/toc.yaml

@@ -42,6 +42,7 @@ sections:
             filters/page: "| page"
             filters/raw: "| raw"
             filters/resize: "| resize"
+            filters/str: "| str*"
             filters/theme: "| theme"
             filters/time: "| time_[since|tense]"
             filters/trans: "| trans"