[DOC] Harmonize <= methods

Merged: https://github.com/ruby/ruby/pull/15653

compar.c

@@ -141,10 +141,15 @@ cmp_lt(VALUE x, VALUE y)
 
 /*
  *  call-seq:
- *     obj <= other    -> true or false
+ *    self <= other -> true or false
+ *
+ *  Returns whether +self+ is "less than or equal to" +other+;
+ *  equivalent to <tt>(self <=> other) <= 0</tt>:
+ *
+ *    'foo' <= 'foo'  # => true
+ *    'foo' <= 'food' # => true
+ *    'food' <= 'foo' # => false
  *
- *  Compares two objects based on the receiver's <code><=></code>
- *  method, returning true if it returns a value less than or equal to 0.
  */
 
 static VALUE

hash.c

@@ -4888,10 +4888,9 @@ hash_le(VALUE hash1, VALUE hash2)
 
 /*
  *  call-seq:
- *    self <= other_hash -> true or false
+ *    self <= other -> true or false
  *
- *  Returns +true+ if the entries of +self+ are a subset of the entries of +other_hash+,
- *  +false+ otherwise:
+ *  Returns whether the entries of +self+ are a subset of the entries of +other+:
  *
  *    h0 = {foo: 0, bar: 1}
  *    h1 = {foo: 0, bar: 1, baz: 2}

numeric.c

@@ -1738,7 +1738,8 @@ flo_lt(VALUE x, VALUE y)
  *  call-seq:
  *    self <= other -> true or false
  *
- *  Returns +true+ if +self+ is numerically less than or equal to +other+:
+ *  Returns whether the value of +self+ is less than or equal to the value of +other+;
+ *  +other+ must be numeric, but may not be Complex:
  *
  *    2.0 <= 3              # => true
  *    2.0 <= 3.0            # => true
@@ -5081,10 +5082,10 @@ fix_le(VALUE x, VALUE y)
 
 /*
  * call-seq:
- *    self <= real -> true or false
+ *    self <= other -> true or false
  *
- *  Returns +true+ if the value of +self+ is less than or equal to
- *  that of +other+:
+ * Returns whether the value of +self+ is less than or equal to the value of +other+;
+ * +other+ must be numeric, but may not be Complex:
  *
  *    1 <= 0              # => false
  *    1 <= 1              # => true