Add decimeter as unit of length

Close #650

core/i18n/src/main/res/values/units.xml

@@ -14,6 +14,11 @@
         <item quantity="one">kilometer</item>
         <item quantity="other">kilometers</item>
     </plurals>
+    <string name="unit_decimeter_symbol">dm</string>
+    <plurals name="unit_decimeter">
+        <item quantity="one">decimeter</item>
+        <item quantity="other">decimeters</item>
+    </plurals>
     <string name="unit_centimeter_symbol">cm</string>
     <plurals name="unit_centimeter">
         <item quantity="one">centimeter</item>

data/unitconverter/src/main/java/de/mm20/launcher2/unitconverter/converters/LengthConverter.kt

@@ -18,6 +18,11 @@ class LengthConverter(context: Context) : SimpleFactorConverter() {
                     context.getString(R.string.unit_kilometer_symbol),
                     R.plurals.unit_kilometer
             ),
+            MeasureUnitWithFactor(
+                    10.0,
+                    context.getString(R.string.unit_decimeter_symbol),
+                    R.plurals.unit_decimeter
+            ),
             MeasureUnitWithFactor(
                     100.0,
                     context.getString(R.string.unit_centimeter_symbol),

data/unitconverter/src/main/java/de/mm20/launcher2/unitconverter/converters/SimpleFactorConverter.kt

@@ -7,7 +7,7 @@ import de.mm20.launcher2.unitconverter.MeasureUnit
 import de.mm20.launcher2.unitconverter.UnitValue
 
 /**
- * A converter for units that can converted into each other by simply multiplicating with a constant factor
+ * A converter for units that can converted into each other by simple multiplication with a constant factor
  */
 abstract class SimpleFactorConverter: Converter {
     open val standardUnits: List<MeasureUnitWithFactor> = emptyList()