more informative error messages for reshape and reinterpret
add missing vectorized versions of radians2degrees and degrees2radians
"Named arguments" -> "Keyword arguments"

Closes #4768
Also change occurences in `src/*`
Merge pull request #4769 from JuliaLang/sf/namedargs

"Named arguments" -> "Keyword arguments"
Merge pull request #4765 from davidssmith/master

more informative error messages for reshape and reinterpret
Fix spelling in base/sysimg.jl: 'sprcific' -> 'specific'
Merge pull request #4770 from nanosec/spelling

Fix spelling in base/sysimg.jl: 'sprcific' -> 'specific'
fix #4771, missing case for -> in macroexpander