Deprecate skipchars for skipuntil

Closes JuliaLang#36132

The name skipchars does not clearly communicate the functionality
available.

Tests for skipchars were left in place to ensure the @deprecate macro
correctly converted those calls to using skipuntil.

base/deprecated.jl

@@ -208,3 +208,9 @@ macro get!(h, key0, default)
 end
 
 # END 1.5 deprecations
+
+# BEGIN 1.6 deprecations
+
+@deprecate skipchars(pred, io::IO; linecomment=nothing) skipuntil(!pred, io::IO; linecomment=linecomment)
+
+# END 1.6 deprecations

base/exports.jl

@@ -820,7 +820,6 @@ export
     seekend,
     seekstart,
     skip,
-    skipchars,
     skipuntil,
     take!,
     truncate,

base/io.jl

@@ -1069,38 +1069,6 @@ Commit all currently buffered writes to the given stream.
 """
 flush(io::IO) = nothing
 
-"""
-    skipchars(predicate, io::IO; linecomment=nothing)
-
-Advance the stream `io` such that the next-read character will be the first remaining for
-which `predicate` returns `false`. If the keyword argument `linecomment` is specified, all
-characters from that character until the start of the next line are ignored.
-
-# Examples
-```jldoctest
-julia> buf = IOBuffer("    text")
-IOBuffer(data=UInt8[...], readable=true, writable=false, seekable=true, append=false, size=8, maxsize=Inf, ptr=1, mark=-1)
-
-julia> skipchars(isspace, buf)
-IOBuffer(data=UInt8[...], readable=true, writable=false, seekable=true, append=false, size=8, maxsize=Inf, ptr=5, mark=-1)
-
-julia> String(readavailable(buf))
-"text"
-```
-"""
-function skipchars(predicate, io::IO; linecomment=nothing)
-    while !eof(io)
-        c = read(io, Char)
-        if c === linecomment
-            readline(io)
-        elseif !predicate(c)
-            skip(io, -ncodeunits(c))
-            break
-        end
-    end
-    return io
-end
-
 """
     skipuntil(predicate, io::IO; linecomment=nothing)
 

doc/src/base/io-network.md

@@ -43,7 +43,6 @@ Base.redirect_stdin
 Base.redirect_stdin(::Function, ::Any)
 Base.readchomp
 Base.truncate
-Base.skipchars
 Base.skipuntil
 Base.countlines
 Base.PipeBuffer