Documentation: describe a few important parameters

Fixes #1659.
Fixes #1482.

Helps with #1523.

docs/configuration.md

@@ -393,10 +393,58 @@ insert newlines.
 > You might be interested in the [Vertical Multiline](#vertical-multiline)
 > section.
 
+### `danglingParentheses`
+
+While this parameter is not technically under the `newlines` section, it logically belongs there.
+
+```scala mdoc:defaults
+danglingParentheses.callSite = true
+danglingParentheses.defnSite = true
+
+# shortcut to set both
+danglingParentheses = true
+```
+
+```scala mdoc:scalafmt
+danglingParentheses.defnSite = true
+danglingParentheses.callSite = true
+---
+object a {
+  // defnSite
+  def method(
+    a: Int,
+    b: String
+  ): Boolean
+
+  // callSite
+  method(
+    a,
+    b
+  )
+}
+```
+
+```scala mdoc:scalafmt
+danglingParentheses.defnSite = false
+danglingParentheses.callSite = false
+---
+object a {
+  // defnSite
+  def method(
+    a: Int,
+    b: String): Boolean
+
+  // callSite
+  method(
+    a,
+    b)
+}
+```
+
 ### `newlines.alwaysBeforeTopLevelStatements`
 
 ```scala mdoc:defaults
-newlines.alwaysBeforeTopLevelStatements
+newlines.alwaysBeforeTopLevelStatements = false
 ```
 
 ```scala mdoc:scalafmt
@@ -520,6 +568,7 @@ Configuration options and default values:
 
 - `rewrite.redundantBraces.maxLines = 100`
 - `rewrite.redundantBraces.includeUnitMethods = true`
+- `rewrite.redundantBraces.methodBodies = true`
 - `rewrite.redundantBraces.stringInterpolation = true`
 - `rewrite.redundantBraces.generalExpressions = false` (disabled by default due
   to #1147)

docs/installation.md

@@ -109,6 +109,10 @@ editors in their respective parts of the
 
 ## sbt
 
+NB: keep in mind that versions of `scalafmt-core` and `sbt-scalafmt` are released
+independently and don't have to align. The version of `scalafmt-core` is defined
+in the `.scalafmt.conf` configuration file and downloaded dynamically.
+
 ```scala
 // In project/plugins.sbt. Note, does not support sbt 0.13, only sbt 1.x.
 addSbtPlugin("org.scalameta" % "sbt-scalafmt" % "2.2.1")