Bad code in several icons

[cyberalien]

Several icons that use SVG animations have multiple elements with the same id:

• /production/fill/svg/alert-avalanche-danger.svg has multiple elements with id="x"
• /production/fill/svg/alert-falling-rocks.svg has multiple elements with id="x"
• /production/line/svg/alert-avalanche-danger.svg has multiple elements with id="x"
• /production/line/svg/alert-falling-rocks.svg has multiple elements with id="x"
• /production/fill/svg/partly-cloudy-night-hail.svg has 2 symbols with id="i"

Last icon has 2 symbols with same id, other icons have multiple animations with same id. Symbols are used as clip paths, animations are used in timing of other animations, so those ids are actually used and probably used incorrectly.

[cyberalien]

Few more icons with same bugs:

• /production/line/svg/tornado.svg has multiple elements with id="x2" (unused, so not critical)
• /production/line/svg/thunderstorms-rain.svg has multiple animations with id="x1"
• /production/line/svg/thunderstorms-overcast-rain.svg has multiple animations with id="x1"
• /production/line/svg/thunderstorms-night-rain.svg has multiple animations with id="x1"
• /production/line/svg/thunderstorms-night-overcast-rain.svg has multiple animations with id="x1"
• /production/line/svg/thunderstorms-night-extreme-rain.svg has multiple animations with id="x1"
• /production/line/svg/thunderstorms-extreme-rain.svg has multiple animations with id="x1"
• /production/line/svg/thunderstorms-day-rain.svg has multiple animations with id="x1"
• /production/line/svg/thunderstorms-day-overcast-rain.svg has multiple animations with id="x1"
• /production/line/svg/thunderstorms-day-extreme-rain.svg has multiple animations with id="x1"

For most of those icons, both fill and line versions are affected. I've listed only 1 variation.