fix deadlinks and outdated information

src/spec/doc/_type-checking-extensions.adoc

@@ -1113,7 +1113,7 @@ https://github.com/apache/groovy/blob/master/src/test/groovy/transform/stc/TypeC
 class which is linked to
 https://github.com/apache/groovy/tree/master/src/test-resources/groovy/transform/stc[various extension scripts].
 
-An example of a complex type checking extension can be found in the link:markup-template-engine.html[Markup Template Engine]
+An example of a complex type checking extension can be found in the link:templating.html#_the_markuptemplateengine[Markup Template Engine]
 source code: this template engine relies on a type checking extension and AST transformations to transform templates into
 fully statically compiled code. Sources for this can be found
 https://github.com/apache/groovy/tree/master/subprojects/groovy-templates/src/main/groovy/groovy/text/markup[here].

src/spec/doc/core-getting-started.adoc

@@ -116,7 +116,7 @@ sudo port install groovy
 
 ==== Homebrew
 
-If you're on macOS and have https://mxcl.github.com/homebrew[Homebrew] installed, you can run:
+If you're on macOS and have https://brew.sh/[Homebrew] installed, you can run:
 
 [source,shell]
 ----

src/spec/doc/core-metaprogramming.adoc

@@ -3281,8 +3281,8 @@ future, meaning that your transformations _could_ break. Despite that warning, t
 and such a thing rarely happens.
 
 Classes of the Abstract Syntax Tree belong to the `org.codehaus.groovy.ast` package. It is recommended to the reader
-to use the Groovy Console, in particular the AST browser tool, to gain knowledge about those classes. However, a good
-resource for learning is the https://github.com/apache/groovy/tree/master/src/test/org/codehaus/groovy/ast/builder[AST Builder]
+to use the Groovy Console, in particular the AST browser tool, to gain knowledge about those classes.
+Another resource for learning is the https://github.com/apache/groovy/tree/master/subprojects/groovy-astbuilder/src/test/groovy/org/codehaus/groovy/ast/builder[AST Builder]
 test suite.
 
 ==== Macros

src/spec/doc/design-patterns-in-groovy.adoc

@@ -84,4 +84,4 @@ include::_design-pattern-visitor.adoc[leveloffset=+2]
  * _Discusses Visitor, Builder and other Patterns._
 . Brad Appleton (1999). http://www.bradapp.com/docs/pizza-inv.html[Pizza Inversion - a Pattern for Efficient Resource Consumption].
  * _One of the most frequently used patterns by many software engineers!_
-. _Design Patterns in Dynamic Languages_ by Neil Ford. Houston Java User’s Group. Examples in Groovy and Ruby. http://www.oracle.com/technetwork/server-storage/ts-4961-159222.pdf
+. _Design Patterns in Dynamic Languages_ by Neil Ford. https://github.com/nealford/presentations/blob/master/Design%20Patterns%20in%20Dynamic%20Languages%20(Neal%20Ford).pdf[Design Patterns in Dynamic Languages].

src/spec/doc/tools-ide.adoc

@@ -33,7 +33,7 @@ Many IDEs and text editors support the Groovy programming language.
 |https://github.com/textmate/groovy.tmbundle[TextMate]|Yes|No|No
 |http://www.vim.org/[vim]|Yes|No|No
 |http://www.ultraedit.com/[UltraEdit]|Yes|No|No
-|https://www.slickedit.com/products/slickedit/419-the-most-powerful-groovy-editor-in-the-world/[SlickEdit]|Yes|No|No
+|https://www.slickedit.com/[SlickEdit]|Yes|No|No
 |https://editrocket.com/features/groovy_editor.html[EditRocket]|Yes|No|No
 |https://code.visualstudio.com/[VSCode]|Yes|No|https://marketplace.visualstudio.com/items?itemName=NicolasVuillamy.vscode-groovy-lint[Yes]
 |===============================================================

subprojects/groovy-jmx/src/spec/doc/jmx.adoc

@@ -1073,6 +1073,6 @@ If you use an **event listener closure (see above) that accepts a parameter**, y
 
 - http://www.ddj.com/dept/java/184406481?pgno=1[Monitoring the Java Virtual Machine]
 - http://buttso.blogspot.com/2006/05/using-groovy-for-system-management.html[Using Groovy for System Management]
-- https://blogs.oracle.com/sundararajan/entry/groovier_jconsole[Groovier jconsole!]
+- https://web.archive.org/web/20170818125929/https://blogs.oracle.com/sundararajan/groovier-jconsole[Groovier jconsole!]
 - http://jmesnil.net/weblog/2007/05/23/jmx-scripts-with-eclipse-monkey[JMX Scripts with Eclipse Monkey]
 - http://activemq.apache.org/jmx.html[Using JMX to monitor Apache ActiveMQ]

subprojects/groovy-json/src/spec/doc/json-userguide.adoc

@@ -47,7 +47,7 @@ include::../test/json/JsonTest.groovy[tags=parse_text,indent=0]
 ----
 
 Notice the result is a plain map and can be handled like a normal Groovy object instance. `JsonSlurper` parses the
-given JSON as defined by the http://www.ecma-international.org/publications/files/ECMA-ST/ECMA-404.pdf[ECMA-404 JSON Interchange Standard]
+given JSON as defined by the https://ecma-international.org/publications-and-standards/standards/ecma-404/[ECMA-404 JSON Interchange Standard]
 plus support for JavaScript comments and dates.
 
 In addition to maps `JsonSlurper` supports JSON arrays which are converted to lists.