Guess user location when running weather ""

Omitting colon makes bash substitute default location only when parameter is absent.
Therefore empty city name propagates to wttr.in and allows it to guess.

share/bash-function.txt

@@ -1,7 +1,7 @@
 wttr()
 {
     # change Paris to your default location
-    local request="wttr.in/${1:-Paris}"
+    local request="wttr.in/${1-Paris}"
     [ "$COLUMNS" -lt 125 ] && request+='?n'
     curl -H "Accept-Language: ${LANG%_*}" --compressed "$request"
 }