Rename the setting -noindent into -no-indent.

This is more consistent with most settings, which have dashes
between words.

We keep `-noindent` as an alias (abbreviation) not to break
existing builds that rely on it.

Author: sjrd

compiler/src/dotty/tools/dotc/config/ScalaSettings.scala

@@ -93,7 +93,7 @@ class ScalaSettings extends Settings.SettingGroup with CommonScalaSettings {
   val newSyntax: Setting[Boolean] = BooleanSetting("-new-syntax", "Require `then` and `do` in control expressions.")
   val oldSyntax: Setting[Boolean] = BooleanSetting("-old-syntax", "Require `(...)` around conditions.")
   val indent: Setting[Boolean] = BooleanSetting("-indent", "Together with -rewrite, remove {...} syntax when possible due to significant indentation.")
-  val noindent: Setting[Boolean] = BooleanSetting("-noindent", "Require classical {...} syntax, indentation is not significant.")
+  val noindent: Setting[Boolean] = BooleanSetting("-no-indent", "Require classical {...} syntax, indentation is not significant.").withAbbreviation("-noindent")
   val YindentColons: Setting[Boolean] = BooleanSetting("-Yindent-colons", "Allow colons at ends-of-lines to start indentation blocks.")
 
   /** Decompiler settings */

compiler/src/dotty/tools/dotc/parsing/Parsers.scala

@@ -603,7 +603,7 @@ object Parsers {
       in.currentRegion = f(cur)
       try op finally in.currentRegion = cur
 
-    /** Parse `body` while checking (under -noindent) that a `{` is not missing before it.
+    /** Parse `body` while checking (under -no-indent) that a `{` is not missing before it.
      *  This is done as follows:
      *    If the next token S is indented relative to the current region,
      *    and the end of `body` is followed by a new line and another statement,

compiler/test/dotty/tools/dotc/CompilationTests.scala

@@ -156,7 +156,7 @@ class CompilationTests {
       compileFile("tests/neg-custom-args/infix.scala", defaultOptions.and("-source", "3.1", "-deprecation", "-Xfatal-warnings")),
       compileFile("tests/neg-custom-args/missing-alpha.scala", defaultOptions.and("-Yrequire-targetName", "-Xfatal-warnings")),
       compileFile("tests/neg-custom-args/wildcards.scala", defaultOptions.and("-source", "3.1", "-deprecation", "-Xfatal-warnings")),
-      compileFile("tests/neg-custom-args/indentRight.scala", defaultOptions.and("-noindent", "-Xfatal-warnings")),
+      compileFile("tests/neg-custom-args/indentRight.scala", defaultOptions.and("-no-indent", "-Xfatal-warnings")),
       compileFile("tests/neg-custom-args/extmethods-tparams.scala", defaultOptions.and("-deprecation", "-Xfatal-warnings")),
       compileDir("tests/neg-custom-args/adhoc-extension", defaultOptions.and("-source", "3.1", "-feature", "-Xfatal-warnings")),
       compileFile("tests/neg/i7575.scala", defaultOptions.withoutLanguageFeatures.and("-language:_")),

docs/docs/reference/other-new-features/indentation.md

@@ -5,7 +5,7 @@ title: Optional Braces
 
 As an experimental feature, Scala 3 enforces some rules on indentation and allows
 some occurrences of braces `{...}` to be optional.
-It can be turned off with the compiler flag `-noindent`.
+It can be turned off with the compiler flag `-no-indent`.
 
 - First, some badly indented programs are flagged with warnings.
 - Second, some occurrences of braces `{...}` are made optional. Generally, the rule
@@ -28,7 +28,7 @@ The compiler enforces two rules for well-indented programs, flagging violations
     println("done")  // error: indented too far to the left
     ```
 
- 2. If significant indentation is turned off (i.e. under Scala-2 mode or under `-noindent`) and we are at the  start of an indented sub-part of an expression, and the indented part ends in a newline, the next statement must start at an indentation width less than the sub-part. This prevents errors where an opening brace was forgotten, as in
+ 2. If significant indentation is turned off (i.e. under Scala-2 mode or under `-no-indent`) and we are at the  start of an indented sub-part of an expression, and the indented part ends in a newline, the next statement must start at an indentation width less than the sub-part. This prevents errors where an opening brace was forgotten, as in
 
     ```scala
     if (x < 0)
@@ -349,13 +349,13 @@ end IndentWidth
 
 ### Settings and Rewrites
 
-Significant indentation is enabled by default. It can be turned off by giving any of the options `-noindent`, `old-syntax` and `language:Scala2`. If indentation is turned off, it is nevertheless checked that indentation conforms to the logical program structure as defined by braces. If that is not the case, the compiler issues a warning.
+Significant indentation is enabled by default. It can be turned off by giving any of the options `-no-indent`, `old-syntax` and `language:Scala2`. If indentation is turned off, it is nevertheless checked that indentation conforms to the logical program structure as defined by braces. If that is not the case, the compiler issues a warning.
 
 The Dotty compiler can rewrite source code to indented code and back.
 When invoked with options `-rewrite -indent` it will rewrite braces to
-indented regions where possible. When invoked with options `-rewrite -noindent` it will rewrite in the reverse direction, inserting braces for indentation regions.
+indented regions where possible. When invoked with options `-rewrite -no-indent` it will rewrite in the reverse direction, inserting braces for indentation regions.
 The `-indent` option only works on [new-style syntax](./control-syntax.html). So to go from old-style syntax to new-style indented code one has to invoke the compiler twice, first with options `-rewrite -new-syntax`, then again with options
-`-rewrite -indent`. To go in the opposite direction, from indented code to old-style syntax, it's `-rewrite -noindent`, followed by `-rewrite -old-syntax`.
+`-rewrite -indent`. To go in the opposite direction, from indented code to old-style syntax, it's `-rewrite -no-indent`, followed by `-rewrite -old-syntax`.
 
 ### Variant: Indentation Marker `:`
 

tests/pos/syntax-rewrite.scala

@@ -1,7 +1,7 @@
 // This test source should be invariant under the following 4 compilation steps with options
 //  -rewrite -new-syntax
 //  -rewrite -indent
-//  -rewrite -noindent
+//  -rewrite -no-indent
 //  -rewrite -old-syntax
 object test {