Grammars: Remove use of /i/ in middle of terminals, to support Lark.js

lark/grammars/python.lark

@@ -10,8 +10,8 @@ DEC_NUMBER: /0|[1-9][\d_]*/i
 HEX_NUMBER.2: /0x[\da-f]*/i
 OCT_NUMBER.2: /0o[0-7]*/i
 BIN_NUMBER.2 : /0b[0-1]*/i
-FLOAT_NUMBER.2: /((\d+\.[\d_]*|\.[\d_]+)(e[-+]?\d+)?|\d+(e[-+]?\d+))/i
-IMAG_NUMBER.2: /\d+j/i | FLOAT_NUMBER "j"i
+FLOAT_NUMBER.2: /((\d+\.[\d_]*|\.[\d_]+)([eE][-+]?\d+)?|\d+([eE][-+]?\d+))/
+IMAG_NUMBER.2: /\d+[jJ]/ | FLOAT_NUMBER /[jJ]/
 
 
 // Comma-separated list (with an optional trailing comma)