Fix broken links in docstring of repeat (#36376)

This changes the link targets of `^` parseable and more specific.

Author: kimikage

base/strings/basic.jl

@@ -686,7 +686,7 @@ reverseind(s::AbstractString, i::Integer) = thisind(s, ncodeunits(s)-i+1)
 
 Repeat a string `r` times. This can be written as `s^r`.
 
-See also: [`^`](@ref)
+See also: [`^`](@ref :^(::Union{AbstractString, AbstractChar}, ::Integer))
 
 # Examples
 ```jldoctest

base/strings/string.jl

@@ -321,7 +321,8 @@ end
 """
     repeat(c::AbstractChar, r::Integer) -> String
 
-Repeat a character `r` times. This can equivalently be accomplished by calling [`c^r`](@ref ^).
+Repeat a character `r` times. This can equivalently be accomplished by calling
+[`c^r`](@ref :^(::Union{AbstractString, AbstractChar}, ::Integer)).
 
 # Examples
 ```jldoctest

doc/src/base/strings.md

@@ -7,7 +7,7 @@ Base.codepoint
 Base.length(::AbstractString)
 Base.sizeof(::AbstractString)
 Base.:*(::Union{AbstractChar, AbstractString}, ::Union{AbstractChar, AbstractString}...)
-Base.:^(::AbstractString, ::Integer)
+Base.:^(::Union{AbstractString, AbstractChar}, ::Integer)
 Base.string
 Base.repeat(::AbstractString, ::Integer)
 Base.repeat(::AbstractChar, ::Integer)