[DOC] Replace rdoc style codeblocks with markdown style backtick codeblocks in markdown documents (#15900)

Merged-By: tompng <tomoyapenguin@gmail.com>

doc/contributing/documentation_guide.md

@@ -265,16 +265,16 @@ and _never_ when referring to the class itself.
 
 When writing an explicit link, follow these guidelines.
 
-#### +rdoc-ref+ Scheme
+#### `rdoc-ref` Scheme
 
-Use the +rdoc-ref+ scheme for:
+Use the `rdoc-ref` scheme for:
 
 - A link in core documentation to other core documentation.
 - A link in core documentation to documentation in a standard library package.
 - A link in a standard library package to other documentation in that same
   standard library package.
 
-See section "+rdoc-ref+ Scheme" in [links].
+See section "`rdoc-ref` Scheme" in [links].
 
 #### URL-Based Link
 
@@ -297,7 +297,7 @@ The name of a variable (as specified in its call-seq) should be marked up as
 [monofont].
 
 Also, use monofont text for the name of a transient variable
-(i.e., one defined and used only in the discussion, such as +n+).
+(i.e., one defined and used only in the discussion, such as `n`).
 
 ### HTML Tags
 
@@ -491,10 +491,10 @@ Return types:
 
 - If the method can return multiple different types,
   separate the types with "or" and, if necessary, commas.
-- If the method can return multiple types, use +object+.
-- If the method returns the receiver, use +self+.
+- If the method can return multiple types, use `object`.
+- If the method returns the receiver, use `self`.
 - If the method returns an object of the same class,
-  prefix `new_` if and only if the object is not +self+;
+  prefix `new_` if and only if the object is not `self`;
   example: `new_array`.
 
 Aliases:

doc/language/exceptions.md

@@ -504,18 +504,18 @@ These methods return backtrace information:
 By default, Ruby sets the backtrace of the exception to the location where it
 was raised.
 
-The developer might adjust this by either providing +backtrace+ argument
+The developer might adjust this by either providing `backtrace` argument
 to Kernel#raise, or using Exception#set_backtrace.
 
 Note that:
 
-- by default, both +backtrace+ and +backtrace_locations+ represent the same backtrace;
+- by default, both `backtrace` and `backtrace_locations` represent the same backtrace;
 - if the developer sets the backtrace by one of the above methods to an array of
   Thread::Backtrace::Location, they still represent the same backtrace;
 - if the developer sets the backtrace to a string or an array of strings:
-  - by Kernel#raise: +backtrace_locations+ become +nil+;
-  - by Exception#set_backtrace: +backtrace_locations+ preserve the original
+  - by Kernel#raise: `backtrace_locations` become `nil`;
+  - by Exception#set_backtrace: `backtrace_locations` preserve the original
     value;
-- if the developer sets the backtrace to +nil+ by Exception#set_backtrace,
-  +backtrace_locations+ preserve the original value; but if the exception is then
-  reraised, both +backtrace+ and +backtrace_locations+ become the location of reraise.
+- if the developer sets the backtrace to `nil` by Exception#set_backtrace,
+  `backtrace_locations` preserve the original value; but if the exception is then
+  reraised, both `backtrace` and `backtrace_locations` become the location of reraise.

doc/language/options.md

@@ -640,7 +640,7 @@ Option `--encoding` is an alias for
 
 Option `--external-encoding`
 sets the default external encoding for the invoked Ruby program;
-for values of +encoding+,
+for values of `encoding`,
 see {Encoding: Names and Aliases}[rdoc-ref:encodings.rdoc@Names+and+Aliases].
 
 ```console
@@ -662,7 +662,7 @@ For a shorter help message, use option `-h`.
 
 Option `--internal-encoding`
 sets the default internal encoding for the invoked Ruby program;
-for values of +encoding+,
+for values of `encoding`,
 see {Encoding: Names and Aliases}[rdoc-ref:encodings.rdoc@Names+and+Aliases].
 
 ```console

file.c

@@ -5557,7 +5557,7 @@ rb_thread_flock(void *data)
  *  call-seq:
  *    flock(locking_constant) -> 0 or false
  *
- *  Locks or unlocks file +self+ according to the given `locking_constant`,
+ *  Locks or unlocks file `self` according to the given `locking_constant`,
  *  a bitwise OR of the values in the table below.
  *
  *  Not available on all platforms.
@@ -5567,10 +5567,10 @@ rb_thread_flock(void *data)
  *
  *  | Constant        | Lock         | Effect
  *  |-----------------|--------------|-----------------------------------------------------------------------------------------------------------------|
- *  | +File::LOCK_EX+ | Exclusive    | Only one process may hold an exclusive lock for +self+ at a time.                                               |
- *  | +File::LOCK_NB+ | Non-blocking | No blocking; may be combined with +File::LOCK_SH+ or +File::LOCK_EX+ using the bitwise OR operator <tt>\|</tt>. |
- *  | +File::LOCK_SH+ | Shared       | Multiple processes may each hold a shared lock for +self+ at the same time.                                     |
- *  | +File::LOCK_UN+ | Unlock       | Remove an existing lock held by this process.                                                                   |
+ *  | `File::LOCK_EX` | Exclusive    | Only one process may hold an exclusive lock for `self` at a time.                                               |
+ *  | `File::LOCK_NB` | Non-blocking | No blocking; may be combined with `File::LOCK_SH` or `File::LOCK_EX` using the bitwise OR operator <tt>\|</tt>. |
+ *  | `File::LOCK_SH` | Shared       | Multiple processes may each hold a shared lock for `self` at the same time.                                     |
+ *  | `File::LOCK_UN` | Unlock       | Remove an existing lock held by this process.                                                                   |
  *
  *  Example:
  *
@@ -5697,11 +5697,11 @@ test_check(int n, int argc, VALUE *argv)
  *      | <tt>'z'</tt> | Whether the entity exists and is of length zero.                          |
  *
  *  - This test operates only on the entity at `path0`,
- *    and returns an integer size or +nil+:
+ *    and returns an integer size or `nil`:
  *
  *      | Character    | Test                                                                                         |
  *      |:------------:|:---------------------------------------------------------------------------------------------|
- *      | <tt>'s'</tt> | Returns positive integer size if the entity exists and has non-zero length, +nil+ otherwise. |
+ *      | <tt>'s'</tt> | Returns positive integer size if the entity exists and has non-zero length, `nil` otherwise. |
  *
  *  - Each of these tests operates only on the entity at `path0`,
  *    and returns a Time object;