fix #6583, fix #14376, index+search now generated for all projects, many bug fixes with nim doc (#14324)

* refs #6583 fix nim doc output
* changelog
* change default for outDir when unspecified
* cleanups
* --project implies --index

testament/lib/stdtest/specialpaths.nim

@@ -1,5 +1,6 @@
 #[
 todo: move findNimStdLibCompileTime, findNimStdLib here
+xxx: consider moving this to $nim/compiler/relpaths.nim to get relocatable paths
 ]#
 
 import os
@@ -9,22 +10,17 @@ import os
 # This means the binaries they produce will embed hardcoded paths, which
 # isn't appropriate for some applications that need to be relocatable.
 
-const sourcePath = currentSourcePath()
-  # robust way to derive other paths here
-  # We don't depend on PATH so this is robust to having multiple nim
-  # binaries
-
-const nimRootDir* = sourcePath.parentDir.parentDir.parentDir.parentDir
-  ## root of Nim repo
-
-const stdlibDir* = nimRootDir / "lib"
-  # todo: make nimeval.findNimStdLibCompileTime use this
-
-const systemPath* = stdlibDir / "system.nim"
-
-const buildDir* = nimRootDir / "build"
-  ## refs #10268: all testament generated files should go here to avoid
-  ## polluting .gitignore
+const
+  sourcePath = currentSourcePath()
+    # robust way to derive other paths here
+    # We don't depend on PATH so this is robust to having multiple nim binaries
+  nimRootDir* = sourcePath.parentDir.parentDir.parentDir.parentDir ## root of Nim repo
+  stdlibDir* = nimRootDir / "lib"
+  systemPath* = stdlibDir / "system.nim"
+  testsDir* = nimRootDir / "tests"
+  buildDir* = nimRootDir / "build"
+    ## refs #10268: all testament generated files should go here to avoid
+    ## polluting .gitignore
 
 static:
   # sanity check