Format: Default to switch cases on separate lines by default

Currently, the format enforces single lines when possible, but does
not enforce readable column-based alignment (and, moreover, *removes*
such manually added alignment:

    switch( m_orientation )
    {
    case PIN_RIGHT: m_orientation = PIN_UP; break;
    case PIN_UP: m_orientation = PIN_LEFT; break;
    }

Change this to multi-line by default:

    switch( m_orientation )
    {
    case PIN_RIGHT:
        m_orientation = PIN_UP;
        break;
    case PIN_UP:
        m_orientation = PIN_LEFT;
        break;
    }

If the developer wishes for column-aligned single-line cases, this
is permitted, but much be done manually:

    switch( m_orientation )
    {
    case PIN_RIGHT: m_orientation = PIN_DOWN;  break;
    case PIN_UP:    m_orientation = PIN_RIGHT; break;
    }

CHANGE: the _clang-format file to reflect this, and add note about
manual override in the dev docs.

(cherry picked from commit 272c045c37)

Documentation/development/coding-style-policy.md

@@ -467,6 +467,20 @@ The case statement is to be indented to the same level as the switch.
     }
 ~~~~~~~~~~~~~
 
+It is permitted to place all cases on a single line each, if that makes the
+code more readable. This is often done for look-ups or translation functions. In
+this case, you will have to manually align for readability as appropriate and
+reject clang-format's suggested changes, if you use it:
+
+~~~~~~~~~~~~~{.cpp}
+    switch( m_orientation )
+    {
+    case PIN_RIGHT: m_orientation = PIN_UP;    break;
+    case PIN_UP:    m_orientation = PIN_LEFT;  break;
+    case PIN_LEFT:  m_orientation = PIN_DOWN;  break;
+    case PIN_DOWN:  m_orientation = PIN_RIGHT; break;
+    }
+~~~~~~~~~~~~~
 
 # 5. License Statement # {#license_statement}
 There is a the file copyright.h which you can copy into the top of

_clang-format

@@ -7,7 +7,7 @@ AlignOperands: true
 AlignTrailingComments: true
 AllowAllParametersOfDeclarationOnNextLine: true
 AllowShortBlocksOnASingleLine: false
-AllowShortCaseLabelsOnASingleLine: true
+AllowShortCaseLabelsOnASingleLine: false
 AllowShortFunctionsOnASingleLine: false
 AllowShortIfStatementsOnASingleLine: false
 AllowShortLoopsOnASingleLine: false