[docs] Fixing Sphinx warnings to unclog the buildbot

Lots of blocks had "llvm" or "nasm" syntax types but either weren't following
the syntax, or the syntax has changed (and sphinx hasn't keep up) or the type
doesn't even exist (nasm?).

Other documents had :options: what were invalid. I only removed those that had
warnings, and left the ones that didn't, in order to follow the principle of
least surprise.

This is like this for ages, but the buildbot is now failing on errors. It may
take a while to upgrade the buildbot's sphinx, if that's even possible, but
that shouldn't stop us from getting docs updates (which seem down for quite
a while).

Also, we're not losing any syntax highlight, since when it doesn't parse, it
doesn't colour. Ie. those blocks are not being highlighted anyway.

I'm trying to get all docs in one go, so that it's easy to revert later if we
do fix, or at least easy to know what's to fix.

llvm-svn: 276109
diff --git a/llvm/docs/TableGen/LangIntro.rst b/llvm/docs/TableGen/LangIntro.rst
index a148634..c1391e7 100644
--- a/llvm/docs/TableGen/LangIntro.rst
+++ b/llvm/docs/TableGen/LangIntro.rst
@@ -232,7 +232,7 @@
 
 Here is a simple TableGen file:
 
-.. code-block:: llvm
+.. code-block:: text
 
   class C { bit V = 1; }
   def X : C;
@@ -276,7 +276,7 @@
 value.  For example, a new class could be added to the example above, redefining
 the ``V`` field for all of its subclasses:
 
-.. code-block:: llvm
+.. code-block:: text
 
   class D : C { let V = 0; }
   def Z : D;
@@ -295,7 +295,7 @@
 bindings (which may optionally have defaults) that are bound when used.  Here is
 a simple example:
 
-.. code-block:: llvm
+.. code-block:: text
 
   class FPFormat<bits<3> val> {
     bits<3> Value = val;
@@ -316,7 +316,7 @@
 The more esoteric forms of `TableGen expressions`_ are useful in conjunction
 with template arguments.  As an example:
 
-.. code-block:: llvm
+.. code-block:: text
 
   class ModRefVal<bits<2> val> {
     bits<2> Value = val;
@@ -346,7 +346,7 @@
 actual internal data representation expected by the class.  In this case,
 running ``llvm-tblgen`` on the example prints the following definitions:
 
-.. code-block:: llvm
+.. code-block:: text
 
   def bork {      // Value
     bit isMod = 1;
@@ -379,7 +379,7 @@
 
 Here is an example TableGen fragment that shows this idea:
 
-.. code-block:: llvm
+.. code-block:: text
 
   def ops;
   def GPR;
@@ -405,7 +405,7 @@
 multiclass.  Using a multiclass this way is exactly equivalent to instantiating
 the classes multiple times yourself, e.g. by writing:
 
-.. code-block:: llvm
+.. code-block:: text
 
   def ops;
   def GPR;
@@ -432,7 +432,7 @@
 A ``defm`` can also be used inside a multiclass providing several levels of
 multiclass instantiations.
 
-.. code-block:: llvm
+.. code-block:: text
 
   class Instruction<bits<4> opc, string Name> {
     bits<4> opcode = opc;
@@ -473,7 +473,7 @@
 the class list must start after the last multiclass, and there must be at least
 one multiclass before them.
 
-.. code-block:: llvm
+.. code-block:: text
 
   class XD { bits<4> Prefix = 11; }
   class XS { bits<4> Prefix = 12; }
@@ -516,7 +516,7 @@
 specified as a double quoted string immediately after the '``include``' keyword.
 Example:
 
-.. code-block:: llvm
+.. code-block:: text
 
   include "foo.td"
 
@@ -532,7 +532,7 @@
 File-scope "let" expressions take a comma-separated list of bindings to apply,
 and one or more records to bind the values in.  Here are some examples:
 
-.. code-block:: llvm
+.. code-block:: text
 
   let isTerminator = 1, isReturn = 1, isBarrier = 1, hasCtrlDep = 1 in
     def RET : I<0xC3, RawFrm, (outs), (ins), "ret", [(X86retflag 0)]>;
@@ -559,7 +559,7 @@
 levels of multiclass instantiations. This also avoids the need of using "let"
 expressions within subsequent records inside a multiclass.
 
-.. code-block:: llvm
+.. code-block:: text
 
   multiclass basic_r<bits<4> opc> {
     let Predicates = [HasSSE2] in {
@@ -587,7 +587,7 @@
 body, substituting iterator values for iterator references in the body.
 Example:
 
-.. code-block:: llvm
+.. code-block:: text
 
   foreach i = [0, 1, 2, 3] in {
     def R#i : Register<...>;
@@ -598,7 +598,7 @@
 may be nested. If there is only one item in the body the braces may be
 elided:
 
-.. code-block:: llvm
+.. code-block:: text
 
   foreach i = [0, 1, 2, 3] in
     def R#i : Register<...>;