add missing backquotes for __init__ docs (#37805)

Author: aviatesk

base/docs/basedocs.jl

@@ -106,7 +106,7 @@ kw"module"
 `__init__()` function in your module would executes immediately *after* the module is loaded at
 runtime for the first time (i.e., it is only called once and only after all statements in the
 module have been executed). Because it is called *after* fully importing the module, `__init__`
-functions of submodules will be executed *first*. Two typical uses of __init__ are calling
+functions of submodules will be executed *first*. Two typical uses of `__init__` are calling
 runtime initialization functions of external C libraries and initializing global constants
 that involve pointers returned by external libraries.
 See the [manual section about modules](@ref modules) for more details.