Reorganize website docs (#1806)

Updates to chisel3 documentation for website:
* guard code examples with mdoc and fix errors encountered along the way
* move some website content here vs splitting the content across two repos
* Bring in the interval-types and loading memories content so that it will be visible from the website
* remove all references to the wiki (deprecated)
* Remove reference to Wiki from the README
* fix tabbing and compile of chisel3-vs-chisel2 section
* Appendix: faqs now guarded and compile
* FAQs: move to resources section

1 files changed, 38 insertions, 24 deletions

diff --git a/docs/src/appendix/chisel3-vs-chisel2.md b/docs/src/appendix/chisel3-vs-chisel2.md
index bfd20348..cafd29e3 100644
--- a/docs/src/appendix/chisel3-vs-chisel2.md
+++ b/docs/src/appendix/chisel3-vs-chisel2.md
@@ -5,6 +5,9 @@ section: "chisel3"
 ---
 
 # Chisel3 vs Chisel2
+```scala mdoc:invisible
+import chisel3._
+```
 
 ## Chisel2 Migration
 For those moving from Chisel2, there were some backwards incompatible changes
@@ -12,55 +15,66 @@ and your RTL needs to be modified to work with Chisel3. The required
 modifications are:
 
  - Wire declaration style:
-   ```scala
-   val wire = UInt(width = 15)
-   ```
+```scala
+  val wire = UInt(width = 15)
+```
    becomes (in Chisel3):
-   ```scala
-   val wire = Wire(UInt(15.W))
-   ```
+```scala mdoc:compile-only
+  val wire = Wire(UInt(15.W))
+```
 
  - I/O declaration style:
-   ```scala
+```scala
    val done = Bool(OUTPUT)
-   ```
+```
    becomes (in Chisel3):
-   ```scala
+```scala mdoc:compile-only
    val wire = Output(Bool())
-   ```
+```
 
  - Sequential memories:
-   ```scala
+```scala mdoc:invisible
+import chisel3._
+val enable = Bool()
+```
+
+```scala
    val addr = Reg(UInt())
    val mem = Mem(UInt(8.W), 1024, seqRead = true)
    val dout = when(enable) { mem(addr) }
-   ```
+```
    becomes (in Chisel3):
-   ```scala
+```scala mdoc:compile-only
    val addr = UInt()
    val mem = SyncReadMem(1024, UInt(8.W))
    val dout = mem.read(addr, enable)
-   ```
+```
 
    Notice the address register is now internal to the SyncReadMem(), but the data
    will still return on the subsequent cycle.
 
- - Generating Verilog with
-   ```scala
+ - Generating Verilog for a module:
+```scala mdoc:invisible
+import chisel3._
+class Hello extends RawModule
+```
+
+```scala
    object Hello {
      def main(args: Array[String]): Unit = {
        chiselMain(Array("--backend", "v"), () => Module(new Hello()))
      }
    }
-   ```
+```
    becomes (in Chisel3):
-   ```scala
+```scala mdoc:compile-only
+   import chisel3.stage.ChiselStage
    object Hello {
      def main(args: Array[String]): Unit = {
-       chisel3.Driver.execute(Array[String](), () => new Hello())
+       (new ChiselStage).emitVerilog(new Hello())
      }
    }
-   ```
+```
 
  - Package changes:
    - Chisel.log2Ceil -> chisel3.util.log2Ceil
@@ -143,14 +157,14 @@ hardware objects), based on specific imports.
 This allows designs to move from less strict front end checks (largely compatible with Chisel2), to stricter checking,
 on a file by file basis, by adjusting specific import statements.
 
-```scala
-    import chisel3.core.ExplicitCompileOptions.Strict
+```scala mdoc:compile-only
+    import chisel3.ExplicitCompileOptions.Strict
 ```
 
 enables stricter connection and usage checks, while
 
-```scala
-    import chisel3.core.ExplicitCompileOptions.NotStrict
+```scala mdoc:compile-only
+    import chisel3.ExplicitCompileOptions.NotStrict
 ```
 
 defers these checks to the `firrtl` compiler.