fixed some broken links and markdown in the docs

docs/designers/language-custom-functions/index.md

@@ -1,4 +1,4 @@
-# Custom Functions
+# Custom Tags
 
 Smarty comes with several custom plugin functions that you can use in
 the templates.

docs/designers/language-custom-functions/language-function-eval.md

@@ -22,7 +22,7 @@ output to the template.
 >     templates.
 >
 > -   Evaluated variables are compiled on every invocation, the compiled
->     versions are not saved! However, if you have [caching](../../programmers/caching.md)
+>     versions are not saved! However, if you have [caching](../../api/caching/basics.md)
 >     enabled, the output will be cached with the rest of the template.
 >
 > -   If the content to evaluate doesn't change often, or is used

docs/designers/language-custom-functions/language-function-fetch.md

@@ -28,7 +28,7 @@ ftp and display the contents.
     > If security is enabled, and you are fetching a file from the local
     > file system, `{fetch}` will only allow files from within the
     > `$secure_dir` path of the security policy. See the
-    > [Security](../../programmers/advanced-features/advanced-features-security.md) section for details.
+    > [Security](../../api/security.md) section for details.
 
 -   If the `assign` attribute is set, the output of the `{fetch}`
     function will be assigned to this template variable instead of being

docs/designers/language-custom-functions/language-function-html-image.md

@@ -20,7 +20,7 @@ automatically calculated from the image file if they are not supplied.
     from. If not given, the web server's document root
     `$_ENV['DOCUMENT_ROOT']` is used as the base. If security is
     enabled, then the image must be located in the `$secure_dir` path of
-    the security policy. See the [Security](../../programmers/advanced-features/advanced-features-security.md)
+    the security policy. See the [Security](../../api/security.md)
     section for details.
 
 -   `href` is the href value to link the image to. If link is supplied,
@@ -37,7 +37,7 @@ automatically calculated from the image file if they are not supplied.
 >
 > `{html_image}` requires a hit to the disk to read the image and
 > calculate the height and width. If you don't use template
-> [caching](../../programmers/caching.md), it is generally better to avoid `{html_image}`
+> [caching](../../api/caching/basics.md), it is generally better to avoid `{html_image}`
 > and leave image tags static for optimal performance.
 
 ## Examples

docs/designers/language-custom-functions/language-function-textformat.md

@@ -1,6 +1,6 @@
 # {textformat}
 
-`{textformat}` is a [block function](../../programmers/plugins/plugins-block-functions.md) used to
+`{textformat}` is a block tag used to
 format text. It basically cleans up spaces and special characters, and
 formats paragraphs by wrapping at a boundary and indenting lines.