App: Expression: rename lexer and parser files

Rename files according 7d233dc ("Gui: Rename generated lexer files
to match core naming pattern"). Note that C space errors (space
before tabs, spaces on blank lines, etc.) still need to be fixed
manually after regenerating lexer file.

src/App/ExpressionParser.sh

@@ -1,6 +1,8 @@
 #!/usr/bin/env sh
 
-cd "$(dirname "$0")"
-
-flex -v -olex.ExpressionParser.c ExpressionParser.l
-bison -d -v -Wall -oExpressionParser.tab.c ExpressionParser.y
+(cd "$(dirname "$0")" && \
+  flex -v -oExpression.lex.c Expression.l && \
+  bison -d -v -Wall -oExpression.tab.c Expression.y && \
+  sed -i '1s|^|// clang-format off\n|' Expression.tab.c && \
+  sed -i '1s|^|// clang-format off\n|' Expression.lex.c \
+)