Make English the source language of the interface text

Every tr() source string in the code and the forms is now the English
text, and French is a translation (qet_fr.ts) like the other languages.
Generated, not hand-edited: master ef795a21e5 converted by
qet-en-source (harness 4c4ddc9).

3144 messages get an English source, 665 already had one, 0 left French; 8 shared-wording pairs disambiguated.
C++: 2904 literals in 233 files. Forms: 809 strings in 65 files. All 34 .ts files re-keyed; qet_fr.ts filled.
lupdate check: PASS. What each of 38 languages shows, old vs new: same 118266, English instead of French 38433, comment fallback 51, differences 0.

sources/autoNum/ui/numparteditorw.ui

@@ -76,7 +76,7 @@
       <bool>false</bool>
      </property>
      <property name="toolTip">
-      <string>Mettre à 0 pour un chiffre qui n'avance que par le report d'un chiffre cyclique suivant (ex: le "0" de "0.7")</string>
+      <string>Set to 0 for a number that only increases by carrying over the next digit in the cycle (e.g. the ‘0’ in ‘0.7’)</string>
      </property>
      <property name="alignment">
       <set>Qt::AlignCenter</set>
@@ -107,7 +107,7 @@
       </sizepolicy>
      </property>
      <property name="toolTip">
-      <string>Valeur à laquelle ce chiffre revient à 0 en incrémentant le chiffre précédent (0 = pas de cycle)</string>
+      <string>The value at which this figure returns to 0 when the previous figure is incremented (0 = no cycle)</string>
      </property>
      <property name="alignment">
       <set>Qt::AlignCenter</set>
@@ -138,7 +138,7 @@
       </size>
      </property>
      <property name="toolTip">
-      <string>Format d'affichage : une suite de zéros donne le nombre minimum de chiffres (00 = 07, 000 = 007). Vide = largeur naturelle du type.</string>
+      <string>Display format: a sequence of zeros specifies the minimum number of digits (00 = 07, 000 = 007). Blank = the natural width of the type.</string>
      </property>
      <property name="placeholderText">
       <string>0</string>